What does God see in Israel that so affronts Him that He has to swear "by His holiness"? Israel had every opportunity that the Gentiles did not have: His calling, His promises, His Word, His laws. He gave the Israelites these gifts to help them develop into His sons and daughters, but God sees them as diametrically opposite of Himself. Should not God expect to see some of His characteristics in His sons?
John Ritenbaugh warns that the pride of Jacob (or his offspring) coupled with the incredible ability to make tremendous technological advances, blinds Israel to its devastating moral deficit. Amos begins with a description or cataloging of the sins of Israel's enemies, followed by a harsh indictment of its own sins and a roar of wrath (or justice), followed by the encirclement by its enemies and its ultimate fall. Thankfully, after punishing His people, God will redeem them and faithfully fulfill His covenant with them. God, in His sovereignty, will do what He must to bring Abraham's seed to repentance and salvation, including allowing crisis, hardship, humiliation, and calamity. As the Israel of God, we dare not complacently take our special covenant-relationship for granted, realizing that His plumbline (a combination of grace and law) will measure us, testing our spirituality while showing absolutely no favoritism or partiality. We need to see ourselves from God's perspective.
John Ritenbaugh observes that ancient Israel had at the core of its religion (as well as its dominant cultural norm) an obsession to serve or please the self at the expense of justice and truth and the best interests of the socially disadvantaged. Because of Israel's excessive self-seeking and self-serving pride, God threatens to remove His protection, allowing its people to go into captivity. Pride (the catalyst for Laodiceanism) causes people to reject God and to follow idolatrous ways. Israel's leaders should 1) never be content with the way things are, 2) never let care and concern for self take priority over the welfare of others, 3) covet peace with God, but only on His terms, 4) choose things that are more excellent, and 5) embrace morality.