In Hosea 4:17 it is recorded that our Lord said, “Ephraim is joined unto idols, let him alone.”
There comes a time, said John MacArthur, when God abandons men, where He lets a people go, lets them go to the consequences of their own sinful choices, useless ideologies, evolutionary cosmogonies, scientism as an instrument of man's will, occultism, spiritism, and sodomy as an alternative lifestyle. They refuse to accept His counsel. They spurn all His reproof, as Proverbs says, so they eat the fruit of their own choices and they have to be satisfied with the useless devices they have chosen. Of the Pharisees Jesus said, “Let them alone, they are blind leaders of the blind,” Matthew 15:14, the most terrifying words, “Let them alone.” (A Nation Abandoned by God, John MacArthur)
It’s a frightening thing to think about that. It's frightening to think that you might be abandoned by the Holy God, that the opportunity for salvation is past, that the day of grace is over, that at the same time grace is withdrawn delusion envelopes and darkens the minds of the abandoned:
"....and with all the deception of wickedness for those who perish, because they did not receive the love of the truth so as to be saved. For this reason God will send upon them a deluding influence so that they will believe what is false, in order that they all may be judged who did not believe the truth, but took pleasure in wickedness." 2 Thessalonians 2: 10-12
Let them alone, for in righteous judgment the Lord has sent them strong delusion that by their wicked actions the wicked will fall into greater wickedness that their sin be punished by sin. Thus the judgment of the Lord is that they should believe lies. Being destitute of the love of the truth, they are necessarily led to believe lies. While their minds are open to all manner of falsehood, stupidity, depravity and delusion they are tightly sealed within an impenetrable bubble closed to the Light of Truth. So "Let them alone, they are blind leaders of the blind."