XII. There was no need that a particular precept concerning the baptism of infants should be given because it was known to the disciples that infants were circumcised. It therefore sufficed that there was a general command to baptize all nations, under which the particular is contained.

XIII. The baptism of Christ (performed when he was in his thirtieth year) cannot overthrow infant baptism. All the acts of Christ (which do not pertain to doctrine) are not forthwith to be imitated; otherwise baptism would have to be received only in the thirtieth year (which however our opponents do not say). There was a peculiar reason for his waiting until that time; not only because only in the preceding year was the baptism of John instituted, but also on account of the type of the Levitical priests (who although received in their twenty-fifth year into the priestly college, before their thirtieth year were not admitted to the exercise of their office). Christ (not needing baptism) could safely put it off. But our case is different, we being conceived and born in sin.

XIV. John admitted no one to baptism unless he confessed his sins because he was dealing with the baptism of adults and those called to the Christian church. But it does not follow that the same should be done with infants who are already in the church.

XV. A sign whose virtue depends on the disposition of the receiving subject differs from one whose virtue depends on the promise of the institutor. The former sign is to no purpose applied to one not understanding it; but it is not so with the latter (such as baptism and circumcision). Again, a subject receptive of the sign differs from one perceptive of it also; infants can be the former, although not the latter. Third, a sign is useless applied to one not understanding, or about to understand (which cannot be said of an infant).

XVI. Baptism is called the sacrament of repentance; not because it requires that beforehand in everyone to be baptized, but because it binds the baptized to the desire of it, whether in the present (when they are capable of it) or in the future.

XVII. Sacraments without faith in the user are said to be empty ceremonies with regard to adults; not with regard to infants, in whom (for a salutary use of baptism) the promise is sufficient and the grace of the covenant (which is sealed on the part of God), even though as yet there is not an answer and restipulation on the part of the baptized (as is evident in circumcision, Gen. 17:7).

Francis Turretin, Institutes of Elenctic Theology, ed. James T. Dennison Jr., trans. George Musgrave Giger, vol. 3 (Phillipsburg, NJ: P&R Publishing, 1992–97), 19.20.12–17 (p. 418–19).