Matthew 24:3 While he was sitting upon the Mount of Olives, the disciples approached him privately, saying: “Tell us, When will these things be, and what will be the sign of your presence and of the conclusion of the system of things?”
4 And in answer Jesus said to them: “Look out that nobody misleads YOU; 5 for many will come on the basis of my name, saying, ‘I am the Christ,’ and will mislead many. 6 YOU are going to hear of wars and reports of wars; see that YOU are not terrified. For these things must take place, but the end is not yet.
Matthew24:23 “Then if anyone says to YOU, ‘Look! Here is the Christ,’ or, ‘There!’ do not believe it. 24 For false Christs and false prophets will arise and will give great signs and wonders so as to mislead, if possible, even the chosen ones. 25 Look! I have forewarned YOU. 26 Therefore, if people say to YOU, ‘Look! He is in the wilderness,’ do not go out; ‘Look! He is in the inner chambers,’ do not believe it. 27 For just as the lightning comes out of eastern parts and shines over to western parts, so the presence of the Son of man will be. 28 Wherever the carcass is, there the eagles will be gathered together.
So from the signs on the earth that we see, we will know that Jesus is in the heavens.
When Jesus ascended into heaven, according to the record, “a cloud caught him up from their vision.” (Ac 1:9) The disciples did not see Jesus riding away on a cloud, but rather, the cloud obscured their vision of him. This helps us to understand Jesus’ words concerning his presence: “They will see the Son of man coming in a cloud with power and great glory,” and Revelation’s statement: “He is coming with the clouds, and every eye will see him.” (Lu 21:27; Mt 24:30; Re 1:7) In past cases clouds represented invisible presence; but observers could “see” the meaning with their mental “eyes.” In this case the physical occurrences that are visible would cause the one looking to “see” or realize that Christ is invisibly present.—See also Mt 24; Mr 13; Re 14:14.
Matthew 24:7 “For nation will rise against nation and kingdom against kingdom, and there will be food shortages and earthquakes in one place after another. 8 All these things are a beginning of pangs of distress.
9 “Then people will deliver YOU up to tribulation and will kill YOU, and YOU will be objects of hatred by all the nations on account of my name.10 Then, also, many will be stumbled and will betray one another and will hate one another. 11 And many false prophets will arise and mislead many; 12 and because of the increasing of lawlessness the love of the greater number will cool off. 13 But he that has endured to the end is the one that will be saved. 14 And this good news of the kingdom will be preached in all the inhabited earth for a witness to all the nations; and then the end will come.
the first ones are pretty easy to understand, but the increasing of lawlessness means from the Christian churches.
Matthew 7:21 “Not everyone saying to me, ‘Lord, Lord,’ will enter into the kingdom of the heavens, but the one doing the will of my Father who is in the heavens will. 22 Many will say to me in that day, ‘Lord, Lord, did we not prophesy in your name, and expel demons in your name, and perform many powerful works in your name?’ 23 And yet then I will confess to them: I never knew YOU! Get away from me, YOU workers of lawlessness.
This term lawlessness is taken from the Pharisees. They were to teach the people Jehovah's law. But instead they added their own and made it very burdensome for the people. In the time of the end Christendom also were teach the people Jehovah's word about Jesus, but instead they have taught people from pagan ideas. The trinity, life after death, idolatry, they set up a clergy class, they say that you don't have to do anything, just come to church and all will be OK. You don't have to preach about Jesus and Jehovah. This is part of the sacred secret that will be known in the last days. So Christendom is the man of lawlessness class.
John specifically mentions apostates as among those of the antichrist by referring to those who “went out from us,” abandoning the Christian congregation. (1Jo 2:18, 19) It therefore includes “the man of lawlessness” or “son of destruction” described by Paul, as well as the “false teachers” Peter denounces for forming destructive sects and who “disown even the owner that bought them.”—2Th 2:3-5; 2Pe 2:1
Christendom came from the congregation that Jesus and his followers started . But have deviated from Jesus teachings.
The apostle Peter drew a parallel between the apostasy from Christianity and that which occurred in the natural house of Israel. He said: “However, there also came to be false prophets among the people, as there will also be false teachers among you. These very ones will quietly bring in destructive sects and will disown even the owner that bought them, bringing speedy destruction upon themselves. Furthermore, many will follow their acts of loose conduct, and on account of these the way of the truth will be spoken of abusively.” Peter goes on to point out that these would exploit the congregation but that “the destruction of them is not slumbering.”—2Pe 2:1-3.