From Commentary on John (ca. 1575)
Once Thomas had seen and touched and recognized the face and familiar voice of the Lord, then full faith welled up in him and he fell to the ground and exclaimed, “My Lord and my God!” This is a very brief but complete formula of the true faith and confession. For Thomas concluded from the true raising or resurrection of the body that this Jesus was the Lord, that is, the Redeemer and King of all things, and God, that is, the life and preservation of all creatures.
Nor does he cry out, “You are the Lord and God,” but “My Lord and my God!” For true faith believes that the Lord God is its own Lord and God, that is, believes that the omnipotent, supremely wise, and merciful God and Lord is well-disposed toward the believer, and that he freely disperses and liberally pours out all his good things for the use of believers.
This is, therefore, the confession of St. Thomas, “O Lord Jesus, I confess that you are my Lord and God, for you gave yourself unto death for my sins, and redeemed me from condemnation, and you rose form the dead for my sake so that your life should be my own and so that I might one day also rise by your power.”
Heinrich Bullinger (1504-1575) was a Swiss Reformed pastor and theologian, the principal leader of the Church in Zurich for over forty years. He was among the primary drafters of the First and Second Helvetic Confessions, and worked with John Calvin to establish a common basis of teaching on the Eucharist among the Swiss Reformed Churches.