Ox is clean (Deu 14:4). The donkey is unclean because it does not chew the cud (Leviticus 11:26)
NIV Deuteronomy 22:
10 Do not plow with an ox and a donkey yoked together.
Don't marry someone who does not believe in the LORD, Deuteronomy 7:
3 You shall not intermarry with them, giving your daughters to their sons or taking their daughters for your sons, 4a for they would turn away your sons from following me, to serve other gods.
Note the sexual as well as the religious connotations, Numbers 25:
1 While Israel lived in Shittim, the people began to whore with the daughters of Moab. 2 These invited the people to the sacrifices of their gods, and the people ate and bowed down to their gods. 3 So Israel yoked himself to Baal of Peor.
The yoke is an image of two animals tightly bound together, working together, under the direction of the master/driver.
Solomon had many unbelieving wives, 1 Kings 11:
4 As Solomon grew old, his wives turned his heart after other gods, and his heart was not fully devoted to the LORD his God, as the heart of David his father had been.
These imageries and commands are carried over in the NT, 2 Corinthians 6:
14 Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness? 15 What accord has Christ with Belial? Or what portion does a believer share with an unbeliever? ...
16 What agreement has the temple of God with idols? For we are the temple of the living God;
1 Corinthians 7:
39b if her husband dies, she is free to marry anyone she wishes, but he must belong to the Lord.
By logic and by commands, Christians should only marry Christians.
See also
Will you date a non-Christian?.
