Charles H. Spurgeon on Psalms 78:17

And they sinned yet more against him. He does not say that they sinned only, but that they sinned against God. And they sinned yet more against him, namely, God. Against what God? Against him who had delivered them by great and unheard of wonders out of Egypt, who had led them as free men across the Red Sea with a dry foot, who had continued to lead and to protect them will pillars of cloud and fire by day and night, and had given them to drink abundantly of water drawn from the arid rock. Against this God they had added sin to sin. Simply to sin is human, and happens to the saints even after they have received grace: but to sin against God argues a singular degree of impiety. To sin against God is to injure and dishonour him in things immediately pertaining to himself. So they sinned against God, because after so many distinguished proofs and testimonies of his care made manifest to them, they continued to think and speak evil against him. All sins indeed, of whatever class they may be, are done against God, because they are opposed to his will; but those which are committed peculiarly against God, are certainly greater than others. Such are those wrought against his name, goodness, providence, power, truth, and worship, and against those things which specially concern him, whatever they may be. So we read of the sins of the sons of Eli, 1Sa 2:24-25: "It is no good report that I hear: ye make the Lord's people to transgress. If one man sin against another, the judge shall judge him; but if a man sin against the Lord, who shall intreat for him?" Musculus.