What does Matthew 12:1 mean?

In the previous verses, Jesus offered rest for the souls of those who were weary and burdened if they would take His yoke on them (Matthew 11:28–30). His meaning was not about physical work, but the spiritual condition of the people. Jesus' faithful Jewish listeners were weary and burdened due to the excessive legalism and restrictions placed on them by their religious leaders. Most prominent among these were the Pharisees: an extremely legalistic sect who added many layers to the laws given to Moses.

This verse begins a confrontation between the Pharisees and Jesus about one of these difficult restrictions.

Jesus and His disciples are walking through a planted field of grain. They begin to pluck off the heads of grain and eat them. This is not theft; the law allowed people to pluck grain or grapes by hand from a neighbor's field or vineyard, so long as one did not harvest the grain with a sickle or put the grapes in a bag (Deuteronomy 23:24–25). This allowed those who were poor to find food in the harvest season without taking too much from the profits of their neighbors.

However, the Pharisees will still pounce on Christ and His followers. This event takes place on the Jewish Sabbath. The Sabbath began at sundown on Friday evening and continued through sundown on Saturday evening. According to Pharisees traditional interpretation of—and addition to—the law, this is "work." That, in their view, violates the fourth commandment (Exodus 20:8–11).