According to Isaiah 1:3, Israel does not know Jehovah, not even as the ox knows his owner, and the donkey, his master's manger. If Israel does not know their Master as a person, they should at least know His manger as a place of eating. Even such an animal as a donkey knows this. Israel, however, had become a people who did not know God at all, and He complained about this.
In chapters one, three, and five, Isaiah speaks concerning Israel's iniquities and corruptions.
Israel was a sinful nation, a people heavy with iniquity and not heavy with holiness. They were also the seed of evildoers and were children acting corruptly (1:4a).
They had forsaken Jehovah, having despised their Holy One (1:4b). They had been called to be holy, yet they despised the Holy One, who had called them to holiness. They also became estranged and went backward. This means that they left God.
Isaiah 1:10 speaks of "rulers of Sodom" and "people of Gomorrah." This indicates that their rulers were like those of Sodom and their people like those of Gomorrah.
Jehovah did not delight in their sacrifices and offerings, and their incense was an abomination to Him (1:11-13a). Because they rejected God to the uttermost, the incense they burned to Him was an abomination to Him. He would not accept their sacrifices and offerings and would not be pleased with their incense. Moreover, His soul hated their Sabbaths and feasts (vv. 13b-14a). Their way of observing these was an offense to Him, and He was weary of bearing them (v. 14b). The people had exhausted His forbearance. Thus, He would hide His eyes from them and would not hear their multiplied prayers. Furthermore, their hands were full of blood (v. 15).