Why will they take the mark of the beast so readily?
They will take the mark so readily because, having heard and rejected the gospel, they are condemned and already deluded by a sovereign act of God. This delusion causes them to believe the Antichrist is the man the world is looking for, so they accept his mark at the drop of a hat.
Les explains that the only ones completely condemned are those who heard the gospel, plainly understood it, were convicted by it, and then rejected it. They will be the first to embrace the Antichrist and take the mark of the beast. Les says they will accept that mark at the drop of a hat because they have already been completely deluded by a sovereign act of God into thinking the Antichrist is the man the world is looking for. Believers, however, have nothing to fear, because the mark is only for the tribulation people.