Amos is one of the 12 Minor Prophets in the Torah. He prophesied from about 775 to 750 B.C.E., and came from Tekoa about 12 miles south of Jerusalem. During his time as a prophet, the kingdom of Israel had expanded and had taken control over trade routes throughout the country. A new class of the rich and wealthy took shape in Israel, and the gap between the rich and the poor grew noticeably larger. Amos pointed out that the poor did not share in the new riches of Israel, and charges the priests with corruption on the grounds that they encouraged the rich to bring elaborate gifts to the Temple for God.
Amos accused the rich of exploiting the poor, for while the rich claim to honor God with lavish sacrifices, they do not give to the poor or forsake debts, and many of the debtors are sold off as slaves. Amos prophesied that the Temple would be destroyed if the Israelites continued to be unjust. "The shrines of Isaac shall be laid waste, and the sanctuaries of Israel reduced to ruin" (7:9). Amos was committed to justice for all people, rich and poor: "But let justice well up like water, Righteousness like a mighty stream" (5:24).
Sources: Wikipedia; Telushkin, Joseph. Biblical Literacy: The Most Important People, Events, and Ideas of the Hebrew Bible. NY: William Morrow and Co., 1997.