In our study of Hosea chapter eight we will compare proper worship of God with the altars of sin that plagued Israel at the time of the prophet. Throughout the Bible, an altar is a place for man to meet and worship God but, as we shall see, God's people had been corrupted and their worship was not accepted.
"'Put the trumpet to your lips! An eagle is over the house of the Lord because the people have broken my covenant and rebelled against my law.'" NIV translation
During their time in the wilderness, the trumpet was used to sound an alarm as well as to summon God's people for a meeting and to move out of camp. Here, God gives a warning to Israel that judgment is coming swiftly. This judgment is coming because they had broken the covenant of God. A covenant is like a peace treaty where the one with authority lays down the rules in which the subjects are to live their lives. In this case, blessing was promised by God if His people would obey His rules for living. If they did not obey, they would be cursed (miss out on blessings from God).
"'Israel cries out to me, "O our God, we acknowledge you!" But Israel has rejected what is good; an enemy will pursue him.'" NIV translation
Not only did they reject following the ways of God but they did so even as they were calling on His name. God's covenant was meant to give them guidance into all of the good things of life but, because they rejected His instructions, they were going in the wrong direction. In much the same manner, many today have accepted Jesus Christ but are not walking in His ways.
"'They set up kings without my consent; they choose princes without my approval. With their silver and gold they make idols for themselves to their own destruction.'" NIV translation
This is speaking of the fact that, after the division of the kingdom, the kings of Israel were not from the line of David. This led to Ahab and his marriage to Jezebel who came from Baal worship. She and Ahab led the people of the northern kingdom (Israel) into idolatry and that is what this verse is talking about. The same type of thing can happen today in the life of a Christian if they choose to marry someone who does not know Jesus Christ.