I’d like to draw out an important aspect of the Reformed tradition’s teaching on baptism. As the WCF 28.6 puts it: “the efficacy of baptism is not tied to that moment of time where in it is administered.” What this means is that in certain cases regeneration and faith comes before the administration of the water, and other times the water is administered and later on comes regeneration and faith.
We shouldn’t think that baptizing someone is like the explorer collecting rare insects who rushes to suspend them in resin. We aren’t trying to lock in the faith before it gets away. We’re applying this water as a witness to Christ’s promise to beget and sustain the faith of those whom He calls. Regardless of whether that faith has already arisen or is yet to arise.