I am on a bit of a baptism kick. If you are not interested in this topic feel free to visit later. I have some other stuff lined up. Here is another quote from Pierre Marcel’s book on infant baptism. All spelling and punctuation is the author’s though I did change gaoler to jailer.

Let us observe also that, according to Acts, the religious instruction of proselytes is carried out with disconcerting speed! It scarcely lasts a few hours…

In Acts 2 the instruction of proselytes commences at 9 am and they are baptized before evening. The Ethiopian eunuch is baptized after a brief conversation with Philip. By order of the glorified Christ Saul is immediately baptized. Cornelius and many others are baptized the same day as they receive instruction. The Philippian jailer is baptized within the hour-“straightway;” and so it goes on. It is impossible to assume that these proselytes had had time to live really and concretely in Christ or to display evidently all the fruits of faith before their baptism. The Apostles did not even think of judging concerning their sincerity and the depth of their convictions. Many were baptized who, as we have observed earlier, turned back from Christ. At the first sign of faith and repentance, and following on their decision to be disciples and to live thenceforward a new life in view of the life eternal, they received baptism. We point to the Church’s conviction that it was God who was acting, in His Son, by the Holy Spirit, and that the promise, once received, would in due course produce its fruits in the lives of those baptized. The idea of setting up a community of “proved” Christians, who would then be admitted to baptism, is not found in the Apostolic Church. This breadth of the Church, this liberality of reception, despite is accompanying dangers, is most remarkable. 

Later on Marcel says this:

The visible Church is administered by men. If, then, the Church were composed only of regenerate individuals, it would be necessary for its ministers, or for the Church itself to be able to read the very hearts of its members and to be absolutely infallible in their judgments concerning man’s internal state. It is, indeed, true that the New Testament teaches that faithful ministers and members of the Church ought to “discern the spirits” as they manifest themselves, but nowhere has Christ promised to the Church or to any individual the gift of probing men’s hearts in order to decide whether the regeneration of grace has been effective in them or not, and if so to what degree.

This point is an important one because it undercuts the idea that Christ wants us to know for sure, in every way possible, that those who come into the church are truly regenerate. Clearly that is not what is going on in Acts. In Acts there is little if any gap between the profession of faith and baptism. Peter and Paul do not seem worried about the sincerity of the profession, how mature they are, or how much they know. My Baptist brothers would change their churches dramatically if they took this approach with converts, including young children even if they never became paedo-baptists. Why would the profession of faith of a four year old not be valid unless you hold to an artificial line in the sand about entrance into the covenant body that is not found in the New Testament? For more on this you can read this blog post where I interact with Tim Challies.