Ephesians 2:8 For by grace you have been saved through faith, and that not of yourselves;
it is the gift of God,
A proof that the gift referred to must include and is faith.
A person would know that God's grace is a gift from Him, not something a person earns. Grace is coming from God, not from man's works.
Salvation also is a work of God not something that you earned by your works.
Jonah 2:9
But I will sacrifice to You With
the voice
of thanksgiving; I will pay what I have vowed.
Salvation is of the Lord.”
But a person might be tempted to think their faith is something they gained and grew inside themselves on their own without God granting that to them.
God has granted to you to believe in Christ.
Philippians 1
27 Only let your conduct be worthy of the gospel of Christ, so that whether I come and see you or am absent, I may hear of your affairs, that you stand fast in one spirit, with one mind striving together for the faith of the gospel, 28 and not in any way terrified by your adversaries, which is to them a proof of perdition,
but [f]to you of salvation, and that from God.
29
For to you it has been granted on behalf of Christ, not only to believe in Him, but also to suffer for His sake, 30 having the same conflict which you saw in me and now hear
is in me.
.