1 Corinthians 9:2

2Ifεἰto othersἄλλοιςnotοὐκI amεἰμὶan apostleἀπόστολος,yetἀλλάat leastγεto youὑμῖνI amεἰμι,theἡforγὰρsealσφραγίςof myμουtheτῆςapostleshipἀποστολῆςyouὑμεῖςareἐστεinἐν[the] Lordκυρίῳ.

If I am not an apostle to others, yet indeed I am to you⁺; for you⁺ are the seal of my apostleship in the Lord.