"What is the harvest? The vast majority of Bible commentators say that it is God’s wrath and judgment upon the nations. Generally they refer to the “blood flowing even unto the horses’ bridles” as the portrayal of horrid war and great massacre. I have no hesitation whatever in telling you that the harvest is not a work of judgment! That is proved by its being the same in kind as the firstfruits which have preceded it! Such as the firstfruits are, such is the harvest. Let me explain."
"The picture in the first part of chapter fourteen of the Revelation is that of the Lamb upon mount Zion and the one hundred and forty-four thousand with Him. As John beholds the scene, he is told that the 144,000 upon mount Zion are those who follow the Lamb whithersoever He goeth, who have the Father’s name written on their foreheads, and they are redeemed from among men, being the FIRSTFRUITS unto God and to the Lamb. The term “firstfruits” is drawn from the well-known offering of “firstfruits” under the Old Testament law of Israel, in which the first portion of any harvest was gathered prior to the full harvest and dedicated to God, in token that the whole belonged to Him, and was recognized as His. These firstfruits were chosen because they were the very first of the grain in the field to ripen. Hence it always implies that something of the same kind will follow it. If there was a field of wheat, the firstfruits, the very first of the ripened grain, would be offered up to God, following which the entire field of wheat would eventually come to the same condition of maturity, though not offered up to God in the same special way for His unique purpose. Thus, the 144,000 are the firstfruits of God’s redemption, the very first of all the Lord’s people to enter into full and complete redemption in spirit, soul, and body, and into the full likeness, image, and stature of Jesus Christ as sons of the Father! Many have supposed that the manifest sons of God are to be eternally unique, different from all the rest of God’s people. But such cannot be! The firstfruits are not firstfruits because they are different, nor because they are better; they are firstfruits simply because they are FIRST!"
Much more in the link:
"Many people also confuse the word “harvest” with judgment. Untold thousands of Bible teachers teach that when the Son of man comes with His sickle and casts it into the earth, He is actually mowing down His enemies with great destruction and blood. What strange delusions the carnal mind invents! While the Greek noun therismos (harvest) with the verb therizo could have been used of the mowing down of enemies, they are never so used in the Greek Old Testament (Septuagint), even in the passages where judgment is symbolically likened to a reaping; and in the New Testament they are used of the ingathering of men into the kingdom of God (Mat. 9:37; Mk. 4:29; Lk. 10:2; Jn. 4:35-38). It is furthermore significant to note that the Son of man is armed, not with the sword that slays, but with the sickle that reaps! Who is more peaceful, more joyful and expectant, than the reaper in the harvest field even though he carries in his hand the sharp sickle? And to His disciples Jesus said, “Lift up your eyes, and look on the fields; for they are white already to harvest. And he that reapeth…gathereth fruit unto eternal life: that he that soweth and he that reapeth may rejoice together” (Jn. 4:35-36). Harvest is a good thing, the subject of the first promise of the renewed earth (Gen. 8:22). Wheat, or corn, the result of harvest is good. Its color is good: “the fields are white already to harvest.” Harvest is the result of seed sown. “Thrust in Thy sickle and reap; for the time is come for Thee to reap” is to say, “The harvest which Thou art to reap is ripe; the seed which Thou has sown hast now grown up; the earth which Thou hast cultivated has produced this golden grain, and it is fit that Thou shouldest gather it in.” What is this grain that grows out of the earth and which is now (in our text) fully ripe and ready to be harvested? Ah, it is those of whom the Lord spoke when He said, “Except a grain of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit” (Jn. 12:24). Now the seed sown by the great Sower is the “word of the kingdom.” The result is “the children of the kingdom.” The Gospels give one testimony as to the meaning of harvest; showing that it relates to the SPIRITUAL STATURE of the people of God!"