St. Paul rejects plural marriage:
Timothy 3:1-5
“This saying is trustworthy: whoever aspires to the office of bishop desires a noble task. Therefore, a bishop must be irreproachable, married only once, temperate, self-controlled, decent, hospitable, able to teach, not a drunkard, not aggressive, but gentle, not contentious, not a lover of money. He must manage his own household well, keeping his children under control with perfect dignity; for if a man does not know how to manage his own household, how can he take care of the church of God?”
Titus 1:5-6:
“For this reason I left you in Crete so that you might set right what remains to be done and appoint presbyters in every town, as I directed you, on condition that a man be blameless, married only once, with believing children who are not accused of licentiousness or rebellious.”