King James Version
If I be not an apostle unto others, yet doubtless I am to you: for the seal of mine apostleship are ye in the Lord.English Standard Version
If to others I am not an apostle, at least I am to you, for you are the seal of my apostleship in the Lord.New International Version
Even though I may not be an apostle to others, surely I am to you! For you are the seal of my apostleship in the Lord.