Thankful people give thanks for all the good God does.
“Oh, that men would give thanks to the Lord for His goodness, and for His wonderful works to the children of men!” (Psalms 107:8, NKJV.)
that they’re redeemed
“Oh, give thanks to the LORD, for He is good! For His mercy endures forever. Let the redeemed of the LORD say so, whom He has redeemed from the hand of the enemy” (Psalms 107: 1-2, NKJV)
that Christ leads them into victory.
“Now thanks be to God who always leads us in triumph in Christ, and through us diffuses the fragrance of His knowledge in every place. For we are to God the fragrance of Christ among those who are being saved and among those who are perishing.” (2 Corinthians 2:14-15, NKJV.)
that God qualifies them.
“giving thanks to the Father who has qualified us to be partakers of the inheritance of the saints in the light.” (Colossians 1:12, NKJV)