Central to understanding verses 4-15 is the word "seek," which appears four times: three times in relation to seeking God Himself and once to seeking good. The charge to seek God is not in the sense of searching to find Him?because He had already revealed Himself to them to some degree?but of seeking to be like Him.
A second important element is the listing of a number of their sins, all of which are what we would call "social sins." Amos mentions the "poor" twice, but he does not necessarily imply a person with little money. The term includes them, but here the meaning is "weak." The poor are those whom we would say have little or no economic, political, or judicial "clout" or "pull." The sins Amos addresses are matters of the strong taking advantage of the weak.
He also mentions other sins that afflict the poor, such as bribery, unjust judgments in the courts, truth being ridiculed, and righteous testimony being thrown out. Amos especially indicts Israel's corrupt court system.
Undoubtedly, the most important element in this passage, due to its impact on most of the instruction in the chapter, is the mention of Bethel, Beersheba, and Gilgal in verse 5. Amos notes these places because the Israelites were holding their festivals there. His overall warning to the Israelites is, "Don't go there because God is not there. Seek God instead." The rest of the chapter tells why God is not there, why what they were doing is unacceptable to Him, and what He will do about it.
John W. Ritenbaugh
Amos 5 and the Feast of Tabernacles