Wherefore if ( ἐα Ìν οὖν, if therefore). The Lord proceeds to make the matter more plain by entering into details which the "here" and "there" of Matthew 24:23 had not sufficiently denoted. He (Christ) is in the desert.
If there was a partial fulfilment of this warning at the siege of Jerusalem, when some impostors tried to persuade the people that Messiah was in the wilderness, preparing to march to their relief, it is to have its chief accomplishment just before the final consummation.
Go not forth. Be not deluded into following any local deceiver. The definite place of appearance proves its falsity (see Matthew 24:27). The secret chambers; in penetralibus (Vulgate). When Christ comes the second time, he will not come as at Bethlehem, in secret, in a corner.
If any pretender should be announced under such conditions, they were to put no belief in him. These were simple tests which all could apply. To limit the Lord's appearance to particular persons or to a particular place, was to incur fatal error.