This verse finishes the question Jesus began in Luke 6:3: "Have ye not read...?" Barnes notes that the case was recorded in the Old Testament, "and therefore one with which they ought to have been acquainted." David, hungry and in need, ate bread that the law reserved for priests, and gave it to his men.

Barnes explains Jesus' point: David was "fleeing before Saul, weary and hungry," and his act had passed without condemnation, showing "that in cases of necessity the laws did not bind a man." Matthew Henry puts it this way: "Ceremonial appointments may be dispensed with, in cases of necessity." Barnes adds that "David, among the Jews, had high authority," and that "the necessity of the disciples justified them."

Luke records no reply from the Pharisees. Jesus followed His question with a declaration: "The Son of man is Lord also of the sabbath" (Luke 6:5). Gill says this was "a full answer to their cavils," that is, to their petty objections. The conflict did not end there. On another sabbath the scribes and Pharisees watched Him to find an accusation (Luke 6:6-7).

The shewbread was twelve loaves set in two rows "upon the pure table before the LORD," renewed "every sabbath," and the law said, "it shall be Aaron's and his sons'; and they shall eat it in the holy place" (Leviticus 24:5-9). The Greek phrase here, artous tēs protheseōs, means "loaves of the setting forth," bread set out before God. That is why the ESV calls it "the bread of the Presence."

The event Jesus describes is in 1 Samuel 21:1-6. David came to Nob, to "Ahimelech the priest," and asked for bread. The priest had "no common bread" but gave him "hallowed bread," the shewbread that had just been replaced with hot bread (1 Samuel 21:4, 6).

Jesus used Scripture to correct a misuse of Scripture. The Pharisees treated the sabbath rules as if no need could ever outweigh them, but the Bible's own story of David showed that God's ceremonial laws served His people. Matthew Henry notes that the shewbread rule "was dispensed with, when David was by Providence brought into such a strait that he must have either that or none."

The argument also points to Jesus' authority. If David, the anointed king, could do this with his men, how much more could the Son of man defend His own followers? Luke places the claim right after: "the Son of man is Lord also of the sabbath" (Luke 6:5). Mark adds, "The sabbath was made for man, and not man for the sabbath" (Mark 2:27).