Israel is an empty vine - Or, in the same sense, “a luxuriant vine;” literally, “one which poureth out,” poureth itself out into leaves, abundant in switches, (as most old versions explain it,) luxuriant in leaves, emptying itself in them, and empty of fruit; like the fig-tree, which our Lord cursed. For the more a fruit tree putteth out its strength in leaves and branches, the less and the worst fruit it beareth. : “The juices which it ought to transmute into wine, it disperseth in the ambitious idle shew of leaves and branches.” The sap in the vine is an emblem of His Holy Spirit, through whom alone we can bear fruit. “His grace which was in me,” says Paul, “was not in vain.” It is in vain to us, when we waste the stirrings of God’s Spirit in feelings, aspirations, longings, transports, “which bloom their hour and fade” . Like the leaves, these feelings aid in maturing fruit; when there are leaves only, the tree is barren and “nigh unto cursing, whose end is to be burned” Hebrews 6:8.
It bringeth forth fruit for itself - Literally, “setteth fruit to, or on itself.” Luxuriant in leaves, its fruit becomes worthless, and is from itself to itself. It is uncultured; (for Israel refused culture,) pouring itself out, as it willed, in what it willed. It had a rich show of leaves, a show also of fruit, but not for the Lord of the vineyard, since they came to no size or ripeness. Yet to the superficial glance, it was rich, prosperous, healthy, abundant in all things, as was the outward state of Israel under Jehoash and Jeroboam II.
According to the multitude of his fruit - Or more strictly, “as his fruit was multiplied, he multiplied altars; as his land was made good, they made goodly their images.” The more of outward prosperity God bestowed upon them, the more they abused His gifts, referring them to their idols; the more God lavished His mercies on them, the more profuse they were in adoring their idols. The superabundance of God’s goodness became the occasion of the superabundance of their wickedness. They rivaled and competed with and outdid the goodness of God, so that He could bestow upon them no good, which they did not turn to evil. People think this strange. Strange it is, as is all perversion of God’s goodness; yet so it is now. People’s sins are either the abuse of what God gives, or rebellion, because He withholds. In the sins of prosperity, wealth, health, strength, powers of mind, wit, people sin in a way in which they could not sin, unless God continually supplied them with those gifts which they turn to sin. The more God gives, the more opportunity and ability they have to sin, and the more they sin. They are “evil,” not only in despite of God’s goodness, but “because” He is good.