What does Acts 11:9 mean?

In this echo of Acts 10:15, God is telling Peter that the food laws are lifted (Mark 7:19). God had presented Peter with a selection of animals to eat, including many which the Mosaic law forbade. Peter refused, saying he had never eaten anything unclean and he wasn't about to start. To him, he was still a Jew. Jesus was the Jewish Messiah and worshiping Him was the fulfillment of Judaism. As far as Peter was concerned, the Mosaic law still stood (Acts 10:9–16).

God wasn't only talking about food, however. He was talking about whom Peter should eat food with. As soon as the vision finished, Peter was invited to another city to share Jesus' story with a room filled with Gentiles. According to tradition, Peter shouldn't have even entered the house. But he understood from the vision that God had declared these Gentiles clean, and he was not to question God's decision (Acts 10:19–33). Later, he will say that God "made no distinction between us and them, having cleansed their hearts by faith" (Acts 15:9). It is by grace we are saved, through faith (Ephesians 2:8–9). It is not by our actions, our diets, or our ethnicities. If we have accepted Jesus' offer of forgiveness, we are made clean.

This is important for us to remember. Earlier, Jesus had defended His disciples when the Pharisees attacked them for not ceremonially washing their hands before eating. Jesus pointed out that food, which goes in one end and out the other, cannot make a person unclean with God. Darkened, sinful hearts that result in sinful attitudes and actions make a person unfit to worship God (Mark 7:1–23). If the language may be excused, no amount of "excrement" we do, say, feel, or experience can make us unclean if God has declared us clean through the sacrifice of His Son. If we have accepted salvation through Jesus, we will never be unclean again.