'Unfaithful' in the Bible
The person who turns to those who have familiar spirits and to wizards, [being unfaithful to Israel's Maker Who is her Husband, and thus] playing the harlot after them, I will set My face against that person and will cut him off from among his people [that he may not be included in the atonement made for them].
And in the fifth year of King Rehoboam, because they had transgressed and been unfaithful to the Lord, Shishak king of Egypt came up against Jerusalem
In the time of his distress he became still more unfaithful to the Lord -- "this same King Ahaz.
Do not be like your fathers and brethren, who were unfaithful to the Lord, the God of their fathers, so that He gave them up to desolation [to be an astonishment], as you see.
Remember [earnestly] what You commanded Your servant Moses: If you transgress and are unfaithful, I will scatter you abroad among the nations;
Confidence in an unfaithful man in time of trouble is like a broken tooth or a foot out of joint.
Concerning the prophets: My heart [says Jeremiah] is broken within me, all my bones shake; I am like a drunken man, a man whom wine has overcome, because of the Lord and because of His holy words [which He has pronounced against unfaithful leaders].
But you trusted in and relied on your own beauty and were unfaithful to God and played the harlot [in idolatry] because of your renown, and you poured out your fornications upon anyone who passed by [as you worshiped the idols of every nation which prevailed over you] and your beauty was his.
But He replied to them, An evil and adulterous generation (a generation morally unfaithful to God) seeks and demands a sign; but no sign shall be given to it except the sign of the prophet Jonah.
A wicked and morally unfaithful generation craves a sign, but no sign shall 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 (unfaithful) and [preeminently] sinful generation, of him will the Son of Man also be ashamed when He comes in the glory (splendor and majesty) 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 of which he does not know, and will punish him and cut him off and assign his lot with the unfaithful.
You [are like] unfaithful wives [having illicit love affairs with the world and breaking your marriage vow to God]! Do you not know that being the world's friend is being God's enemy? So whoever chooses to be a friend of the world takes his stand as an enemy of God.