There is not such thing as sin.
People do good things as well as bad things
Bad things depend on culture and law.
Having sex with many different women is bad in today's Christian Culture
Having sex with 1000 concubines and wives was a Blessing from Jehovah, the SAME GOD of today's Christian Culture.
So in the Old Testament, Jehovah is OK with having many women to have sex with
In the New Testament Jehovah is not OK with men having sex with many women
If you Change the New Testament with the Koran, then Jehovah is OK with men having Sex with lots of women.
SIN IS A FALLACY-----And Jesus was just a dude that came up with some ideas that appealed to a lot of people just like Charles Taze Russell came up with some ideas that appealed to a lot of people.
Both the teachings of Jesus and Charles Russell eventually evolved into different things and created tons of different sects.