en_tn/rom/12/03.md

because of the grace that was given to me

Here "grace" refers to God's choosing Paul to be an apostle and leader of the church. You can make this explicit in your translation. You can also translate this in an active form. Alternate translation: "because God freely chose me to be an apostle" (See: rc://en/ta/man/translate/figs-explicit and rc://en/ta/man/translate/figs-activepassive)

that everyone who is among you should not think more highly of themselves than they ought to think

"that no one among you should think they are better than other people"

Instead, they should think in a wise way

"But you should be wise in how you think about yourselves"

just as God has given out to each one a certain amount of faith

Paul implies here that believers have different abilities that correspond to their faith in God. Alternate translation: "since God has given each of you different abilities because of your trust in him" (See: rc://en/ta/man/translate/figs-explicit)