Amos now comes to the heart of the matter. In the long run the serious thing is not their crimes (3:9–10), rebellions (3:14) or offense to God’s holiness (4:2) but that, given the chance to repent they did not do so. The heart of the passage (6–11) teaches that in all the varied circumstances of life the Lord is the cause and that his purpose in every act of affliction is to bring his people right back to himself. The initial, ironical command Go (4), introducing an exposure of a religion that failed (4–5), is balanced by a final call to be ready to meet the Lord (a religion that will not fail) in vs 12–13. In between these calls there are seven acts of God aimed at bringing his people back to himself (6–11). In Israel’s case the specific aim of the divine acts was repentance, but the principle is that in every experience of life the Lord is directly at work to bring us close to himself.
Carson, D. A.: New Bible Commentary : 21st Century Edition. 4th ed. Leicester, England; Downers Grove, Ill., USA : Inter-Varsity Press, 1994, S. Am 4:4