Jamieson, Fausset and Brown on 2 Corinthians 1:24

24. Not for that--that is, Not that. "Faith" is here emphatic. He had "dominion" or a right to control them in matters of discipline, but in matters of "faith" he was only a "fellow helper of their joy" (namely, in believing, Ro 15:13; Php 1:25). The Greek is, "Not that we lord it over your faith." This he adds to soften the magisterial tone of 2Co 1:23. His desire is to cause them not sorrow (2Co 2:1, 2), but "joy." The Greek for "helpers" implies a mutual leaning, one on the other, like the mutually supporting buttresses of a sacred building. "By faith (Ro 11:20) ye stand"; therefore it is that I bestow such pains in "helping" your faith, which is the source of all true "joy" (Ro 15:13). I want nothing more, not to lord it over your faith.