The more I think about that question, the more it troubles me. It's the wrong question because polygamy isn't differentiated from monogamy as though they were opposing standards for marital relationships. God doesn't speak any differently about the outcome from the union of a man with one wife over another of his wives. Multiple times throughout the Bible God identifies Himself as the "God of Israel" or the "Lord God of Israel" and Israel is the nation descended from Jacob and his four wives. Passages such as Psalm 72:18 make this distinction most specific: Blessed
be the Lord God, the God of Israel, Who only does wondrous things!
Because the world has been so thoroughly duped and blinded as to who God is, they miss the blessedness of God speaking of Himself as the God of a polygamous family.
So in answer to you church leader's challenge
@Sand Bee, I'd say God speaks of Himself in a most positive manner when He refers to Himself as the God of Israel; a nation descended from Jacob's family. And woe to anyone who speaks against the God of Israel. Shalom