Contradiction with Deuteronomy 7:3
This verse instructs the Israelites not to intermarry with other nations, which contradicts Ruth 1:4 where Mahlon and Chilion marry Moabite women.
Deuteronomy 7:3: Neither shalt thou make marriages with them; thy daughter thou shalt not give unto his son, nor his daughter shalt thou take unto thy son.
Contradiction with Nehemiah 13:23-27
Nehemiah points out the sin of intermarriage with foreign women, which contradicts the marriages in Ruth 1:4.
Nehemiah 13:23-27: In those days also saw I Jews [that] had married wives of Ashdod, of Ammon, [and] of Moab: [had...: Heb. had made to dwell with them]
Contradiction with Ezra 9:12
The verse advises against giving daughters to foreign sons or taking foreign daughters for sons, in contradiction to Ruth 1:4’s intermarriages.
Ezra 9:12: Now therefore give not your daughters unto their sons, neither take their daughters unto your sons, nor seek their peace or their wealth for ever: that ye may be strong, and eat the good of the land, and leave [it] for an inheritance to your children for ever.
Contradiction with 1 Kings 11:2
This verse warns against taking foreign wives, as they will turn the heart away from God, contradicting the actions in Ruth 1:4.
1 Kings 11:2: Of the nations [concerning] which the LORD said unto the children of Israel, Ye shall not go in to them, neither shall they come in unto you: [for] surely they will turn away your heart after their gods: Solomon clave unto these in love.