“Come to Bethel and transgress, at Gilgal multiply transgressions; bring your sacrifices every morning, your tithes every three days,” God says in Amos 4:4. Transgress means “rebellion,” not just sin. As we have seen, God considered Israel's syncretistic approach to religion to be an outright rejection of His way of life.
Amos is speaking sarcastically when he suggests that the people sacrifice and tithe more often. “If you bring your tithes every three days instead of every three years,” he says, “maybe your god, Baal, will respond,” which sounds somewhat like Elijah's sarcastic comments in I Kings 18:27.
“'Offer a sacrifice of thanksgiving with leaven, proclaim and announce the freewill offerings; for this you love, you children of Israel!' says the Lord GOD” (Amos 4:5). Leavening was not allowed to be in any sacrifice: “No grain offering which you bring to the LORD shall be made with leaven, for you shall burn no leaven nor any honey in any offering to the LORD made by fire” (Leviticus 2:11). Only two offerings, the wave loaves on Pentecost (Leviticus 23:17) and the thanksgiving offering (Leviticus 7:11-14), were made with leaven. A sin offering preceded the offering of the wave loaves, the leavening in them representing the sins still in the congregation of Israel.
In Amos 4:5, his sarcasm continues. The Israelites might as well have been making all their sacrifices with leaven because all their traditions, doctrines, customs, and religious duties were nothing but vanity. Even though they were sincere in doing them, they were nevertheless a leaven brought in from the world. In like manner, Jesus tells us to beware of the leaven of the Pharisees and Sadducees (Matthew 16:6-12), that is, of their doctrine and their traditions.
Even a glance at modern religious practices reveals how thoughtlessly people accept the doctrines and traditions they have learned—without proving them. Millions of sincere people attend church every week, celebrate the holidays, and send their children to church schools without ever proving their beliefs. They sing in the choir and donate generously when the plate is passed, but they do not really know—have an intimate relationship with—the god they worship. They blindly accept the leaven they were taught growing up.

