Romans 12:3 — For I say, through the grace given to me, to everyone who is among you, not to think of himself more highly than he ought to think, but to think soberly, as God has dealt to each one a measure of faith.
through the grace given to me — Paul's authority to say this doesn't come from his merit but from God's grace
I have been crucified with Christ; it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself for me (Galatians 2:20).
We should be humble-minded, realizing that anything we do that is pleasing to God comes from God.
to each — points to a diversity of gifts.
A man should not aspire to be something that is not in the will of God for him, because God has made him what he is and has a particular place for him as a Christian. How often we find people who do have some real gift, but who are dissatisfied with the gift they have, a gift which may be lowly but worthy, not spectacular but useful; and so they are desiring to be something else other than what they are and what God has purposed. — Alva J. McClain, Romans: The Gospel of God's Grace, page 210