A.T. Robertson Commentary 1 Corinthians 9:19

"For though I was free from all [men,] I brought myself under bondage to all, that I might gain the more." — 1 Corinthians 9:19 (ASV)

I brought myself under bondage (εμαυτον εδουλωσα). Voluntary bondage, I enslaved myself to all, though free. Causative verb in -οω (δουλοω, from δουλος). The more (τους πλειονας). Than he could have done otherwise. Every preacher faces this problem of his personal attitude and conduct. Note κερδησω (as in verses 20,21,22, but once ινα κερδανω in 21, regular liquid future of κερδαινω) with ινα is probably future active indicative (James 4:13), though Ionic aorist active subjunctive from κερδαω is possible (Matthew 18:15). "He refuses payment in money that he may make the greater gain in souls" (Edwards).