What does Romans 15:17 mean?

I myself am also persuaded about you, my brothers, that you yourselves are full of goodness, filled with all knowledge, able also to admonish others.

But I write the more boldly to you in part, as reminding you, because of the grace that was given to me by God,

that I should be a servant of Christ Jesus to the Gentiles, serving as a priest of the Good News of God, that the offering up of the Gentiles might be made acceptable, sanctified by the Holy Spirit.

For I will not dare to speak of any things except those which Christ worked through me, for the obedience of the Gentiles, by word and deed,

in the power of signs and wonders, in the power of God’s Spirit; so that from Jerusalem, and around as far as to Illyricum, I have fully preached the Good News of Christ;

yes, making it my aim to preach the Good News, not where Christ was already named, that I might not build on another’s foundation.