The phrase "selfish gain" means doing something only for your own benefit or advantage, without considering the needs or feelings of others. Full definition
She speaks the language of love and compassion and her act of love is not motivated by selfish gain. (religion-online.org)
Some well - respected evangelical scholars think this means Paul did not permit a woman of that particular community to teach and dominate a man for selfish gain resulting in licentiousness (see recommended reading). (relevantmagazine.com)