Matthew
Matthew 24:23ESV·traditional attribution

Then if anyone says to you, ‘Look, here is the Christ!’ or ‘There he is!’ do not believe it.

John Calvin Reformed @genevareformer

23. If any one shall then say to you. He again repeats what he had said about impostors, and not without reason; for there was great danger arising from this temptation, that wretched men, while their affairs were in a troubled and desperate condition, would be deceived by false pretenses, would seek phantoms instead of Christ, and would embrace the delusions of Satan, as if they were assistance from God.

John Gill Reformed Baptist @doctorgill

Then if any man shall say unto you,.... Either at the time when the siege shall be begun, and the abomination of desolation standing in the holy place; or during the days of tribulation, whilst the siege lasted; or after those days were shortened, and the city destroyed, and the Roman army was gone with their captives: when some, that were scattered up and down...

Albert Barnes Presbyterian @notesbybarnes

Verse 23. Lo, here is Christ. The Messiah. The Jews expected the Messiah to deliver them from Roman oppression. In the time of these great-calamities they would anxiously look for him, Many would claim to be the Messiah. Many would follow them. Many would rejoice to believe that he was come, and would call on others, Christians with the rest, to follow them. Believe it not.