And because iniquity shall abound, the love of many shall wax cold (Matthew 24:12).
The word that is translated iniquity is the Greek word anomia which can also be translated wickedness. And, the word translated abounds is the Greek word plethuno which means to increase or multiply. The same Greek word translated iniquity is also used to describe the religious leaders in Jesus’ day and the mystery of iniquity when Antichrist will be revealed.
Even so ye also outwardly appear righteous unto men, but within ye are full of hypocrisy and iniquity. (Matthew 23:28)
For the mystery of iniquity doth already work: only he who now letteth [will let], until he be taken out of the way. (2 Thessalonians 2:7)
When Jesus Christ returns He will send His angels to gather those who do iniquity:
The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend, and them which do iniquity; And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth. (Matthew 13:41-42)
And when speaking of the judgment day, Jesus mentions some who prophesied in His name, and refers to them as workers of iniquity.
Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity. (Matthew 7:21-23)
Jesus mentions false prophets that will also arise.
And many false prophets shall rise, and shall deceive many. (Matthew 24:11)
It is quite possible, then, that these false prophets are at least some of the false prophets referred to in Matthew 7:21-23. Since Jesus referred to them as workers of iniquity, it may be at least partially through them that iniquity abounds as mentioned in the next verse, Matthew 24:12. One of the results of their work is that many will be deceived. As a result of the iniquity the love of many will grow cold, and some may even fall away from the faith as is indicated will happen during this time.