'Unfaithful' in the Bible

‘As for the person who turns to mediums [who consult the dead] or to spiritists, to play the prostitute after them, I shall set My face against that person and will cut him off from his people [excluding him from the atonement made for them].

And it came about in King Rehoboam’s fifth year, because they had been unfaithful to the Lord, that Shishak king of Egypt came up against Jerusalem

In the time of his distress, this same King Ahaz became yet more unfaithful to the Lord.

Do not be like your fathers and your brothers, who were unfaithful to the Lord God of their fathers, so that He made them a horror (lifeless, desolate), just as you see.

Please remember the word which You commanded Your servant Moses, saying, ‘If you are unfaithful and violate your obligations to Me I will scatter you [abroad] among the peoples;

Like a broken tooth or an unsteady footIs confidence in an unfaithful man in time of trouble.

Concerning the prophets:My heart [says Jeremiah] is broken within me,All my bones shake;I have become like a drunken man,A man whom wine has overcome,Because of the LordAnd because of His holy words [declared against unfaithful leaders].

“But you trusted in and relied on your beauty and prostituted yourself [in idolatry and its debauched rituals] because of your fame, and you poured out your immoralities on every [willing] passer-by and your beauty was his [as you worshiped the idols of the Gentile nations].

But He replied and said to them, “An evil and adulterous generation [that is morally unfaithful to God] craves and demands a [miraculous] sign; but no sign will be given to it except the sign of the prophet Jonah;

An evil and [morally] unfaithful generation craves a [miraculous] sign; but no sign will be given to it, except the sign of [the prophet] Jonah.” Then He left them and went away.

For whoever is ashamed [here and now] of Me and My words in this adulterous and sinful generation, the Son of Man will also be ashamed of him when He comes in the glory of His Father with the holy angels.”

the master of that servant will come on a day when he does not expect him and at an hour he does not know, and will cut him in pieces, and assign him a place with the unbelievers.

You adulteresses [disloyal sinners—flirting with the world and breaking your vow to God]! Do you not know that being the world’s friend [that is, loving the things of the world] is being God’s enemy? So whoever chooses to be a friend of the world makes himself an enemy of God.