When the apostle says, “Without faith, it is impossible to please God,” he speaks of adults, various example of whom he in the same place commemorates and whom alone the proposed description of faith suits (Hebrews 11.1). Now it is different with infants who please God on account of the satisfaction of Christ bestowed upon them and imputed by God to obtain the remission of their sins, even if they themselves do not apprehend it and cannot apprehend it by a defect of age (15.14.7, vol 2, p. 585).
Nevertheless, while Christian infants don’t have or need adult faith in order to be saved, there is some change inaugurated in elect children within the covenant which grows and flowers over time—one which involves the beginning of faith at an infant level: “Although infants do not have actual faith, the seed or root of faith cannot be denied to them, which is ingenerated in them from early age and in its own time goes forth in act (human instrumentation being applied from without and a greater efficacy of the Holy Spirit within)” (15.14.13, vol 2, p. 586).
While Turretin’s major work was a massive three-volume theology that dealt with opposing views, his nephew, Benedict Pictet, publicized his positions in a much shorter and simpler Christian Theology. Pictet deals with the possibility of infant faith under his discussion of infant baptism. (pp 418-420). He divides baptized infants into four classes.
It is in regard to his third class that Pictet elaborates on the possibility of infant faith. It is clear from his discussion that he regards these children, not as converted in youth, but as brought into a saving relationship with Christ while yet infants. He writes:
But should anyone say, he cannot comprehend the operations of the Holy Ghost in these cases; we reply that the thing ought not to be denied, merely because we do not comprehend it. It is not more difficult to conceive the idea of the Holy Spirit restoring the faculties of the infant, and rendering them capable of receiving evangelical objects, as soon as reason shall dawn, than it is to conceive the idea of original sin, which is nothing else but the depravation of those faculties, inclining them to objects of sense. If we can conceive of the principle of evil before any act of it, why not the principle of good before any act of the same? If Adam had not sinned, his descendants would have been naturally innocent; and why cannot it be conceived, that the Holy Spirit places infants, who are born sinful, in some state of regeneration? The cause of our corruption is the proneness of the soul to follow the motions of the body [Note: I doubt that this account of the nature of original sin is correct. –MH]: why then should we not conceive, that the Holy Spirit prevents the soul from following those motions, and gives it the power of directing them aright?
While Pictet thinks these considerations are relevant to infant baptism, he doesn’t think that the regeneration of elect infants invariably occurs at the time of baptism. He replies to such ideas that
they may obtain all spiritual blessings from the very moment of their birth, but that these may be confirmed in baptism, which is the seal, pledge, or earnest of them; the infant, indeed, knows not what is taking place, but when he arrives at years of discretion, then he recognizes it, and from the knowledge of it, possesses every motive to holiness. Some infants are regenerated in the womb, and before baptism, others in baptism, others after: we assign no particular period.