Albert Barnes on Mark 4:29

Immediately he putteth in the sickle. This is the way with the husbandman. As soon as the grain is ripe, it is cut down. So it is often with the Christian. As soon as he is prepared for heaven, he is taken there. But we are not to press this part of the parable, as if it meant that all are removed as soon as they are fit for heaven. Every parable contains circumstances thrown in to fill up the story, which cannot be literally interpreted. In this, the circumstance of sleeping and rising cannot be applied to Christ; and in like manner the harvest, I suppose, is not to be literally interpreted. Perhaps the whole parable may be differently interpreted. The seed sown may mean the gospel which he was preaching. In Judea its beginnings were small. Yet he would leave it; commit it to his disciples; and return to his Father. The gospel in the meantime, left by him, would take root, spring up, and produce an abundant harvest. In due time he would return, send forth the angels, and gather in the harvest, and save his people for ever.

(1) "brought forth" or, "ripe" (f) "putteth in the sickle" Rev 14:15