Belbab,
You are probably referring to this vaguely worded 4/1/65 Watchtower article "The Love That Leads to Life":
3 Love of that kind must be rare, so rare that it would make Jesus’ true pupils or disciples stand out among all other persons on earth and be their distinguishing mark. It did in Jesus’ day; does it today? Look at the newspapers, listen to the radio reports, or just examine the scene around you wherever you may now happen to be. Do you not see what the apostle Paul said you would, when he wrote: “But know this, that in the last days critical times hard to deal with will be here. For men will be lovers of themselves, lovers of money, . . . disobedient to parents, unthankful, disloyal, having no natural affection, . . . without love of goodness, . . . puffed up with pride, lovers of pleasures rather than lovers of God, having a form of godly devotion but proving false to its power; and from these turn away”? (2 Tim. 3:1-5) Why, Jesus foretold that the lack of true love would be so great that even his own Christian congregation would be seriously affected. Remember, it was not of the world in general but of his own professed followers in the time of the end that he said: “And because of the increasing of lawlessness the love of the greater number will cool off.” That spells danger.—Matt. 24:12.
I believe this is the closest the Society has come to suggesting the prophecy applied to JWs themselves. The 12/1/67 QFR added:
Does Jesus’ prophecy at Matthew 24:12 about the cooling off of the love of the greater number find fulfillment in Christendom or among Jehovah’s Christian witnesses?—P. A., U.S.A.The things that have occurred in this generation show that both Christendom and God’s true servants are involved in the fulfillment of this prophecy. In the twenty-fourth chapter of Matthew Jesus Christ was describing to four of his disciples different aspects of the composite sign that would be observed during his second presence. After mentioning wars, food shortages, earthquakes and persecution of true Christians, he added: “Many false prophets will arise and mislead many; and because of the increasing of lawlessness the love of the greater number will cool off.”—Matt. 24:11, 12.
....
However, those who are actually Christians can also be involved in this prophecy. For a time following the setting up of the Kingdom in 1914 Jehovah’s servants were in a state of spiritual captivity. There was persecution from the outside, and even within the organization of true Christians there were problems. Some had allowed their love for God to grow cold and they tried unlawfully to seize control of the organization. When they failed, they fell away and became an “evil slave” class, opposing those who continued to show true love for God. (Matt. 24:48-51) And over the years others have been influenced by the lawlessness of the world or have let their love die down for some other reason. The cooling off of their love caused them to abandon true worship and to join the imitation Christians, thus adding to the “greater number.”
Yet there appears to be no reason to conclude that the greater number of those in Jehovah’s organization of Christian witnesses now are going to lose their love for God in the future. The lawlessness and lack of love in the world is already well advanced, but most of Jehovah’s witnesses are remaining devoted to God and with strong love. Even so, we each need to be concerned with our own spirituality so that our love for God remains strong. (Matt. 22:37) If that is the case with each one of us, Jesus’ words in the next verse of Matthew chapter 24 will be fulfilled in us: “He that has endured to the end is the one that will be saved.”—Matt. 24:13.
The Society repeated this position in the 10/1/84 QFR:
Do Jesus’ words that “the love of the greater number will cool off” mean that this will occur among true worshipers now?With good reason we believe that Jesus was not foretelling a large-scale loss of love among Jehovah’s people.
The apostles had asked for ‘the sign of Jesus’ presence and of the conclusion of the system of things.’ Jesus foretold wars, earthquakes, food shortages and persecution of Christians. He added: “Because of the increasing of lawlessness the love of the greater number will cool off.”—Matthew 24:3-12.
Much of that prophecy found a fulfillment between then (33 C.E.) and the great tribulation on Jerusalem that the Romans caused in 70 C.E. (Compare Luke 19:41-44; 21:5-28.) During that interval, did the love of most anointed Christians cool off? No. Those who fell away from Christianity during that generation evidently were in the minority. Most Christians experiencing persecution from the Jews kept up “declaring the good news of the word,” displaying love for God, for unbelievers and for fellow Christians. (Acts 8:1-25; 9:36-42) But love did cool off among the Jews, who claimed to be true worshipers. The greater number of them ignored Jesus’ warning, revolted against Rome and resorted to a violent defense of their nation.
Jesus’ prophecy extends beyond the first century and has its major fulfillment today. (Revelation 6:2-8) As with the Jews back then, people have less and less effective love. Millions have turned atheistic. Even in Christendom people tend to show less neighbor love, and church attendances and knowledge of the Bible generally are declining. Many who seem to be religious try to rectify human problems through political causes. So it apparently is among such claimed worshipers of God that love is cooling off.
True Christians, though, must not become complacent. Since some Christians in the first century lost their first love or were distracted from it by problems, we could find our love cooling off. (2 Timothy 2:16-19; Revelation 2:4) While, if that happened, we would be exceptions to most of Jehovah’s people, the fact that it could happen to us individually emphasizes our need to ‘endure to the end’ so as to be saved.—Matthew 24:13.
Cheers,
Rational