It was in speaking of baptism that St. John Chrysostom defined what a mystery of faith is, “We do not behold the things which we see, but some things we see and others we believe...I feel differently on these subjects than an unbeliever ... He, hearing of a washing, counts it merely as water; but I behold not simply the thing which is seen, but the purification of the soul which is by the Spirit.” (Homily 7, 2 on 1 Corinthians) We might go further and say that our baptism is our primary act of faith. The gift of faith is given by God, it is a divine virtue.
This happens through a spirit of co-operation between ourselves and God (which we call synergy). We accept life in Christ by a formula of commitment called the syntaxis, “I commit myself to Christ.” We renounce Satan, in whom evil is personified, by a formula of rejection called the apotaxis, “I renounce Satan, and all his works, all his angels, all his service and all his pride.” We do this by our free will, though, since we cannot save ourselves, in the strength of God, who makes us his sons and daughters, feeding us with the bread of life and enabling us to keep his commandments. This was a very serious commitment, and the Epistle to the Hebrews says it cannot be abrogated, “it is impossible in the case of those who have once been enlightened (that is, received faith and been baptized) and tasted the heavenly gift and shared in the Holy Spirit and tasted the good word of God and the powers of the age to come, and then fallen away, to bring them to repentance again, since they are recrucifying the Son of God for themselves and holding him up to contempt. (Hebrews 6:4-6)” The Church, of course, has consistently taught that the God of mercy, who has commanded us to forgive seventy times seven times, is able to forgive us our sins and weaknesses and failures over and over gain, but this passage from Scripture shows how important our commitment to the good must be.
Baptism is the foundation of our faith. In its narrow meaning, we think of simply as a rite that is celebrated once, but the reality of baptism as the turning from evil and a total commitment to Christ lasts throughout life. Since we cannot live in Christ without his grace, baptism is God constantly acting in our lives. This synergy between God and us must be a living reality, so that every time we do God’s will the Spirit is moving us, and every time we receive Communion, God feeds our bodies and souls. What St. John Chrysostom said about the presence of mystery in baptism is then fulfilled, “[The unbeliever] considers only that my body has been washed; but I have believed that the soul also has become both pure and holy; and I count it the sepulcher, the resurrection, the sanctification, the righteousness, the redemption, the adoption, the inheritance, the kingdom of heaven, the full out-pouring of the Spirit. For not by the sight do I judge of the things that appear, but by the eyes of the mind." (Homily 7, 2 on 1 Corinthians)