The Catechism shows us the link between our prayer to God and our faith.
“No one can say ‘Jesus is Lord’ except by the Holy Spirit.” “God has sent the Spirit of his Son into our hearts, crying, ‘Abba! Father!”‘ This knowledge of faith is possible only in the Holy Spirit: to be in touch with Christ, we must first have been touched by the Holy Spirit. He comes to meet us and kindles faith in us. By virtue of our Baptism, the first sacrament of the faith, the Holy Spirit in the Church communicates to us, intimately and personally, the life that originates in the Father and is offered to us in the Son.
— CCC, 2000, para. 683
We find the definition of faith in Scripture.
Faith is the realization of what is hoped for and evidence of things not seen. — NABRE, 2011, Hebrews 11:1
The rest of that Chapter documents numerous examples from the Old Testament where key individuals acted in faith, based on the word of God, about things that seemed impossible.