The Year of Faith: Act of Faith
Faith is both a gift of God and a human act. The presence of the Holy Spirit infused at baptism moves the heart to believe in God. At the same time, faith is a human act. Endowed by God with intellect and free will man is capable of cooperating with or resisting divine grace. By an act of faith man freely assents to the whole truth revealed by God which the Church proposes for belief.
“It is one of the major tenets of Catholic doctrine that man's response to God in faith must be free” (“Declaration on Human Freedom,” 10).
Source: Evangelization and Catechesis Office, Denver Biblical and Catechetical schools