What does Matthew 6:16 mean?

Jesus has already taught His disciples not to call attention to themselves in public when they give to the needy (Matthew 6:3–4) and when they pray (Matthew 6:6). He has called attention-seekers hypocrites who act out worship God for the praise of other people (Matthew 6:2).

Now He begins to apply the same basic lesson to fasting. Fasting involves abstaining from food and other activities in order to focus on worship, confession, or specific prayers to God (Matthew 4:1–2). Fasting was a regular part of worship for faithful Israelites. The law required fasting once a year on the Day of Atonement (Leviticus 23:27–32), though other seasons of fasting had been added to the Jewish calendar over time. In addition, individuals might fast in order to indicate repentance before God or to bring special requests to Him in times of great need.

The Old Testament commands to fast can be translated with the words "afflict yourself" (Numbers 29:7). In Jesus' era, it seems some religious leaders made a point to do this very publicly. The group known as the Pharisees had a reputation as the most strictly religious people in Israel. They were intensely proud of that status. Scholars suggest the Pharisees fasted two days every week. Jesus says in this verse they disfigured their faces in some way and looked "gloomy" to make sure that everyone who saw them knew they were fasting.

This quest for publicity worked. People saw them, understood they were fasting yet again, and gave them credit for being highly devout. Jesus says here that human approval is the only reward attention-seekers will receive for their fasting. Since their effort was not about God, God will not respond or reward them for it. God said the same to their ancestors about fasting with no real heart change (Zechariah 7:5–6; Matthew 5:120; 6:16–18).