Jamieson, Fausset and Brown on Isaiah 49:26

26. feed ... own flesh--a phrase for internal strifes (Is 9:20).

own blood--a just retribution for their having shed the blood of God's servants (Re 16:6).

sweet wine--that is, must, or new wine, the pure juice which flows from the heap of grapes before they are pressed; the ancients could preserve it for a long time, so as to retain its flavor. It was so mild that it required a large quantity to intoxicate; thus the idea here is that very much blood would be shed (Re 14:10, 20).

all flesh shall, &c.--the effect on the world of God's judgments (Is 66:15, 16, 18, 19; Re 15:3, 4).