Luke 6:3

And Jesus answering them said, Have ye not read even this, what David did, when he was hungry, he, and they that were with him; how he entered into the house of God, and took and ate the showbread, and gave also to them that were with him; which it is not lawful to eat save for the priests alone?

The purpose of Christ in this citation was not to equate his actions with those of David. David's actions were "not lawful," as the Lord here stated; Jesus' actions involved no guilt whatever. The Lord in this appeal to the Scriptures stressed the unfairness, hypocrisy, and deceit of the Pharisees, who improperly accepted David's illegal actions as allowable, freely admitting that David's deeds required no reproof; but who nevertheless falsely charged Jesus and his disciples with the capital offense of sabbath-breaking, basing it on actions completely innocent. If this had not been the case, the Pharisees would merely have said, "Ah, so you admit that you are a sinner just like David." See fuller comment on this in my Commentary on Matthew, Matthew 12:1-12. There is not the slightest hint that Jesus "legalized" David's unlawful actions, thus laying down a new law permitting God's regulations to be abrogated on the basis of "human need." Gilmour's deduction that "Human need can override the letter of the law"[5] is a classical example of fallacious interpretations grafted upon this episode; and yet the same author admitted that "No formal charge of sabbath defilement was ever laid against Jesus."[6] The Pharisees did not allege sabbath-breaking at any of Jesus' trials.

[5] S. MacLean Gilmour, Interpreter's Bible (New York: Abingdon Press, 1952), Vol. VIII, p. 111.

[6] Ibid., p. 113.