Why will the love of many wax cold in the last days?
Love grows cold in the last days because iniquity abounds: fierce persecution, betrayal, and a flood of false prophets wear down the saints until many are offended and turn from serving the Lord to serving their own lusts.
Jesus said plainly in Matthew 24 that because iniquity shall abound, the love of many shall wax cold, and this is tied directly to the persecution and betrayal described just before it. As the spirit of the man of sin comes into power, the saints will be hated, afflicted, and even killed for the name of Christ. Because Christianity is a silent condemnation of sin, the spirit of iniquity comes hardest against those who keep the faith, and this pressure causes many in the church to be offended.
When the offense of suffering strikes, loved ones turn against loved ones, saint against saint, and fathers against sons. The way of righteousness is spoken evil of even by those close to us. Many saints, worn down by these attacks, blame God for allowing the enemy to persecute them so severely, and this offense causes them to turn from serving the Lord to serving the desires of their own heart.
At the same time, many false prophets rise and deceive many. It becomes easy for false prophets to deceive those whose hearts are already full of iniquity, since it is the pure in heart who truly see and know God. Revived lust, renewed wantonness for things, and the success of these false prophets all work together to drag mankind, including many of the saints who were offended by the way of holiness, into the lowest place of sin and degradation.
This is why so much emphasis is placed on overcoming offense beforehand: without constantly rehearsing what the Lord has revealed, believers too will grow a spirit of resentment against the righteousness of God. The shield of faith is described as the only thing able to quench the fiery darts of the enemy in that day, which is why the love of many, without that shield, grows cold under the weight of persecution, betrayal, and deception.
The scriptures
Then shall they deliver you up to be afflicted, and shall kill you: and ye shall be hated of all nations for my name’s sake. And then shall many be offended, and shall betray one another, and shall hate one another. And many false prophets shall rise, and shall deceive many. And because iniquity shall abound, the love of many shall wax cold.
But he that shall endure unto the end, the same shall be saved.
From the books
This answer is drawn from these passages in the Mary Banks Faith Library.