Charles H. Spurgeon on Psalms 78:22

Because they believed not in God, and trusted not in his salvation. This is the master sin, the crying sin. Like Jeroboam, the son of Nebat, it sins and makes Israel to sin; it is in itself evil and the parent of evils. It was this sin which shut Israel out of Canaan, and it shuts myriads out of heaven. God is ready to save, combining power with willingness, but rebellious man will not trust his Saviour, and therefore is condemned already. In the text it appears as if all Israel's other sins were as nothing compared with this; this is the peculiar spot which the Lord points at, the special provocation which angered him. From this let every unbeliever learn to tremble more at his unbelief than at anything else. If he be no fornicator, or thief, or liar, let him reflect that it is quite enough to condemn him that he trusts not in God's salvation.