When they fast, I will not hear their cry; and when they offer burnt offering and an oblation, I will not accept them: but I will consume them by the sword, and by the famine, and by the pestilence.
I will not hear - because their prayers are hypocritical; their hearts are still idolatrous. God never refuses to hear real prayer. The cause of his refusing to hear now was, all their services were formal, and unaccompanied with true repentance of their sin (Jeremiah 7:21-22; Proverbs 1:28; Isaiah 1:15; Isaiah 58:3).
I will consume them by the sword, and by the famine, and by the pestilence - the three of the most severe judgments at once; any one of which would be enough for their ruin (2 Samuel 24:12-13).