Notice what Calvin says about this:
"It may be justly said, that such sacraments are ceremonies, by which God is pleased to train his people, first, to excite, cherish, and strengthen faith within; and, secondly, to testify our religion to men." (Institutes 4:14:19)
According to Calvin, the "Zwinglian" view which doesn't see the sacraments as a means of grace but as an identifying mark or badge, and which is the popular view of most Evangelicals, is only a secondary meaning. He says this even more specifically:
"We approve not, that that which is a secondary thing in sacraments is by them made the first, and indeed the only thing. The first thing is, that they may contribute to our faith in God; the secondary, that they may attest our confession before men. These similitudes are applicable to the secondary reason. Let it therefore remain a fixed point, that mysteries would be frigid (as has been seen) were they not helps to our faith, and adjuncts annexed to doctrine for the same end and purpose." (Institutes 4:14:13)
And also Calvin says of them, "These objectors impair the force, and altogether overthrow the use of the sacraments." (Institutes 4:14:14)
Notice what Calvin says Baptism signifies:
"For Baptism testifies that we are washed and purified; the Supper of the Eucharist that we are redeemed. Ablution is figured by water, satisfaction by blood. [...] In the water and blood we have an evidence of purification and redemption." (Institutes 4:14:22)
Calvin does a great job at explaining his meaning:
"Wherefore, let it be a fixed point, that the office of the sacraments differs not from the word of God; and this is to hold forth and offer Christ to us, and, in him, the treasures of heavenly grace. They confer nothing, and avail nothing, if not received in faith, just as wine and oil, or any other liquor, however large the quantity which you pour out, will run away and perish unless there be an open vessel to receive it. ... God, therefore, truly performs whatever he promises and figures by signs; nor are the signs without effect, for they prove that he is their true and faithful author." (Institutes 4:14:17)
Both Luther and Calvin maintained that Baptism doesn't work ex opre operato, that is, just in the mere performance of the act. Both Calvin and Luther strongly opposed such a view. Luther would say that you do not believe God, or trust his promise that is attached to the Water, then baptism does not confer what it signifies, but becomes a source of condemnation.
Calvin, in his Brief Confession of Faith, summarizes his views nicely:
"I confess that our weakness requires that sacraments be added to the preaching of the word, as seals by which the promises of God are sealed on our hearts, and that two such sacraments were ordained by Christ, viz., Baptism and the Lord’s Supper—the former to give us an entrance into the Church of God—the latter to keep us in it. The five sacraments imagined by the Papists, and first coined in their own brain, I repudiate.
But although the sacraments are an earnest by which we may be rendered secure of the promises of God, I however acknowledge that they would be useless to us did not the Holy Spirit render them efficacious as instruments, lest our confidence, being fixed on the creature, should be withdrawn from God. Nay, I even confess that the sacraments are vitiated and perverted when it is not regarded as their only aim to make us look to Christ for every thing requisite to our salvation, and whenever they are employed for any other purpose than that of fixing our faith wholly in him.
In general, I confess that, as well in the supper as in baptism, God gives in reality and effectually whatever he figures in them, but that to the receiving of this great boon we require to join the word with the signs. In which matter I detest the abuse and perversion of the Papists, who have deprived the sacraments of their principal part, viz., the doctrine which teaches the true use and benefit flowing therefrom, and have changed them into magical impostures.
I likewise confess that water, though it is a fading element, truly testifies to us in baptism the true presence of the blood of Jesus Christ, and of his Spirit; and that in the Lord’s Supper the bread and wine are to us true and by no means fallacious pledges that we are spiritually nourished by the body and blood of Christ. And thus I join with the signs the very possession and fruition of that which is therein offered to us."
If you find what Calvin is trying to say difficult, perhaps Martin Luther is a bit clearer.
Luther, in his Small Catechism, explains:
What is Baptism?--Answer.
Baptism is not simple water only, but it is the water comprehended in God's command and connected with God's Word.
Which is that word of God?--Answer.
Christ, our Lord, says in the last chapter of Matthew: Go ye into all the world and teach all nations, baptising them in the name of the Father, and of the Son, and of the Holy Ghost.
What does Baptism give or profit?--Answer.
It works forgiveness of sins, delivers from death and the devil, and gives eternal salvation to all who believe this, as the words and promises of God declare.
Which are such words and promises of God? Answer.
Christ, our Lord, says in the last chapter of Mark: He that believes and is baptised shall be saved; but he that believes not shall be damned.
How can water do such great things?--Answer.
It is not the water indeed that does them, but the word of God which is in and with the water, and faith, which trusts such word of God in the water. For without the word of God the water is simple water and no baptism. But with the word of God it is a baptism, that is, a gracious water of life and a washing of regeneration in the Holy Ghost, as St. Paul says, Titus, chapter three: By the washing of regeneration and renewing of the Holy Ghost, which He shed on us abundantly through Jesus Christ, our Saviour, that, being justified by His grace, we should be made heirs according to the hope of eternal life. This is a faithful saying.
What does such baptising with water signify?--Answer.
It signifies that the old Adam in us should, by daily contrition and repentance, be drowned and die with all sins and evil lusts, and, again, a new man daily come forth and arise; who shall live before God in righteousness and purity forever.
Where is this written?--Answer.
St. Paul says Romans, chapter 6: We are buried with Christ by Baptism into death, that, like as He was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
And if you doubt that Calvin and Luther are in agreement here, I provide several quotes from Calvin's Strassburg Catechism.
Calvin’s Strasburg Children’s Catechism, dating from 1538-9, he begins with the following questions and answers:
“My child, are you a Christian in fact as well as in name?
Yes, my father.
How is this known to you?
Because I am baptized in the name of the Father and of the Son and of the Holy Spirit.”
This is something that is usually thought to be a Lutheran answer, and thus Calvin shows that he is in agreement with them on this point. Baptism and the Lord's Supper were given primary for our assurance. How do you know you're saved? Because of your feelings or experiences? NO! But because of the promise of God attached to Baptism. That's how Luther and Calvin would respond. They would claim it's objective not subjective. It's outside of you, not in you.
Later, in the same work, Calvin writes: “How did you come into this communion of the church? Through baptism. What is this baptism? It is the washing of regeneration and cleansing from sin.”
“Now baptism was given to us by God for these ends (which I have taught to be common to all sacraments): first to serve our faith before him; secondly, to serve our confession before men…Accordingly, they [e.g., the Zwinglians and Anabaptists] who regarded baptism as nothing but a token and mark by which we confess our religion before men, as soldiers bear the insignia of their commander as a mark of their profession, have not weighed what was the chief point of baptism”
“For inasmuch as [baptism] is given for the arousing, nourishing, and confirming of our faith, it is to be received as from the hand of the Author himself. We ought to deem it certain and proved that it is he who speaks to us through the sign; that it is he who purifies and washes away sins, and wipes out the remembrance of them; that it is he who make us sharers in his death, who deprives Satan of his rule, who weakens the power of our lust; indeed, that it is he who comes into a unity with us so that, having put on Christ, we may be acknowledged God’s children. These things, I say, he performs for our soul within as truly and surely as we see our body outwardly cleansed, submerged, and surrounded with water…And he does not feed our eyes with a mere appearance only, but leads us to the present reality and effectively performs what he symbolises”.
“The first thing that the Lord sets out for us is that baptism should be a token and proof of our cleansing; or (the better to explain what I mean) it is like a sealed document to confirm to us that all our sins are so abolished, remitted, and effaced that they can never come to his sight, be recalled, or charged against us.”
“Baptism also brings another benefit, for it shows us our mortification in Christ, and new life in him…[T]hrough baptism Christ makes us sharers in his death, that we may be engrafted in it”
“But we are not to think that baptism was conferred upon us only for past time, so that for newly committed sins into which we fall after baptism we must seek new remedies of expiation in some other sacraments, as if the force of the former one were spent…For, though baptism, administered only once, seemed to have passed, it was still not destroyed by subsequent sins”
“We now see the reason why Christ employs such magnificent terms, to commend and adorn that ministry which he bestows and enjoins on the Apostles [and their successors, pastors]. It is, that believers may be fully convinced, that what they hear concerning the forgiveness of sins is ratified, and may not less highly value the reconciliation which is offered by the voice of men, than if God himself stretched out his hand from heaven. And the church daily receives the most abundant benefit from this doctrine, when it perceives that her pastors are divinely ordained to be sureties for eternal salvation, and that it must not go to a distance to seek the forgiveness of sins, which is committed to their trust.”
“[The forgiveness of sins] is dispensed to us through the ministers and pastors of the church, either by the preaching of the Gospel [including the declaration of absolution] or by the administration of the sacraments; and herein chiefly stands the power of the keys, which the Lord has gifted to the society of believers. Accordingly, let each one of us count it his own duty to seek forgiveness of sins only where the Lord has placed it.”
These are some of the thoughts and quotes that are going through my head at the moment. Although there are areas I would have objections, (baptismal regeneration is problematic), I tend to agree with Calvin and Luther on the point that baptism is not primarily what I do but what God is doing. Baptism is a means of grace and sanctification, and not a testimony or identifying sign only. In my Baptism, God "represented, sealed, and applied" the forgiveness of sins to me. It is objective, and outside of me. I do not trust in the water, the ritual, or the minister. But I trust in the God whose Word of promise spoken through the minister and to me.