Dan 11:31, Dan 12:11, Mt 24:15-28, 2 Thess 2:1-8
In the Old Testament, God spoke of things that would happen in the last days. (Dan 9:27, Dan 11:31, Dan 12:11)
Dan 9:27 And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make it desolate, even until the consummation, and that determined shall be poured upon the desolate.
Dan 11:31 And arms shall stand on his part, and they shall pollute the sanctuary of strength, and shall take away the daily sacrifice, and they shall place the abomination that maketh desolate.
Dan 12:11 And from the time that the daily sacrifice shall be taken away, and the abomination that maketh desolate set up, there shall be a thousand two hundred and ninety days.
Jesus said that there will be great tribulation when the abomination of destruction prophesied in the book of Daniel is seen standing in the holy place, and false Christs and false prophets will arise and deceive the elect. (Matthew 24:15-28)
Matthew 24:15 When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth, let him understand:) 16 Then let them which be in Judaea flee into the mountains: 17 Let him which is on the housetop not come down to take any thing out of his house: 18 Neither let him which is in the field return back to take his clothes. 19 And woe unto them that are with child, and to them that give suck in those days! 20 But pray ye that your flight be not in the winter, neither on the sabbath day: 21 For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be. 22 And except those days should be shortened, there should no flesh be saved: but for the elect's sake those days shall be shortened. 23 Then if any man shall say unto you, Lo, here is Christ, or there; believe it not. 24 For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect. 25 Behold, I have told you before. 26 Wherefore if they shall say unto you, Behold, he is in the desert; go not forth: behold, he is in the secret chambers; believe it not. 27 For as the lightning cometh out of the east, and shineth even unto the west; so shall also the coming of the Son of man be. 28 For wheresoever the carcase is, there will the eagles be gathered together.
We must not be deceived by false prophets in the last days and must firmly believe that Jesus is the Christ. (2 Thessalonians 2:1-8)
2 Thessalonians 2:1 Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him, 2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand. 3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition; 4 Who opposeth and exalteth himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, shewing himself that he is God. 5 Remember ye not, that, when I was yet with you, I told you these things? 6 And now ye know what withholdeth that he might be revealed in his time. 7 For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way. 8 And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming: