Let us now address ourselves to the next point. What is it that we achieve by holy baptism? Is it not a share in the life that is no longer a prey to death? I hardly think anyone who was in any sense a Christian would deny this. But is this life-giving power inherent in the water which we use for the sacrament? Surely it must be obvious to anyone that bodily ministration alone is ineffectual for our sanctification, when it has not been transformed by sanctification. Further, what gives life to the baptized is the Spirit, as the Lord says of it, using his own words ‘The Spirit gives life’ [John 6, 63]. But it does not only give life when it is received through faith or the perfecting of grace, but also there must be faith in the Lord before this, and through this also life-giving grace is communicated to believers, as the Lord says ‘He brings to life to whom he wills’ [John 5, 21]. But, since the grace communicated by the Son is itself derived from the unbegotten spring, this must mean that belief in the Father, who gives life to all, must come first as the Apostle says [cf 1 Tim. 6, 13]. From this source, as from a spring that bubbles forth life, comes the life-giving grace, through the Only Begotten Son, who is the true life and is then perfected in those who are deemed worthy by the action of the Holy Ghost.
~ Against the Macedonians 19
There’s a lot that can be up for interpretation in this statement. I could easily see a Baptist try to capitalize on the part about faith needing to be present before baptism. The one thing that is clear is that Nyssa does not see baptism as working strictly ex opere operato. He also thinks that baptismal regeneration is a given. It is obvious to all who would even claim to be a Christian. He can’t imagine anyone denying it.