For afore the harvest, when the bud is perfect, and the sour grape is ripening in the flower, he shall both cut off the sprigs with pruning hooks, and take away and cut down the branches.

Wesley's Notes

18:5 For - Before they receive the end of their hopes. When - When the bud or flower is turned into a grape, which gives hopes of good vintage. He - The Lord. The branches - Instead of gathering the grapes, shall cut down the tree, and throw it into the fire.

Jamieson-Fausset-Brown Bible Commentary

5. For-rather, "But."

perfect-perfected. When the enemy's plans are on the verge of completion.

sour grape . flower-rather, "when the flower shall become the ripening grape" [Maurer].

sprigs-the shoots with the grapes on them. God will not only disconcert their present plans, but prevent them forming any future ones. Horsley takes the "harvest" and vintage here as referring to purifying judgments which cause the excision of the ungodly from the earth, and the placing of the faithful in a state of peace on the earth: not the last judgment (Joh 15:2; Re 14:15-20).

Matthew Henry's Concise Commentary

18:1-7 God's care for his people; and the increase of the church. - This chapter is one of the most obscure in Scripture, though more of it probably was understood by those for whose use it was first intended, than by us now. Swift messengers are sent by water to a nation marked by Providence, and measured out, trodden under foot. God's people are trampled on; but whoever thinks to swallow them up, finds they are cast down, yet not deserted, not destroyed. All the dwellers on earth must watch the motions of the Divine Providence, and wait upon the directions of the Divine will. God gives assurance to his prophet, and by him to be given to his people. Zion is his rest for ever, and he will look after it. He will suit to their case the comforts and refreshments he provides for them; they will be acceptable, because seasonable. He will reckon with his and their enemies; and as God's people are protected at all seasons of the year, so their enemies are exposed at all seasons. A tribute of praise should be brought to God from all this. What is offered to God, must be offered in the way he has appointed; and we may expect him to meet us where he records his name. Thus shall the nations of the earth be convinced that Jehovah is the God, and Israel is his people, and shall unite in presenting spiritual sacrifices to his glory. Happy are those who take warning by his judgment on others, and hasten to join him and his people. Whatever land or people may be intended, we are here taught not to think that God takes no care of his church, and has no respect to the affairs of men, because he permits the wicked to triumph for a season. He has wise reasons for so doing, which we cannot now understand, but which will appear at the great day of his coming, when he will bring every work into judgment, and reward every man according to his works.