He knows full well how spiritually disastrous a poor marriage can be and , therefore , commanded the Israelites not to enter into marriage covenants with worshipers of other gods .
The above sentence is very complicated. Please provide me a simplified synonymous version consisting of multiple sentences:
God knows full well that a bad marriage can be spiritually disastrous . This is why he ordered the Israelites not to enter into marriages with worshipers of other gods .