Luke 6:3
And Jesus answering them said, Have ye not read so much as this, what David did, when himself was an hungred, and they which were with him; And Jesus answering them said, Have ye not read so much as this, what David did, when himself was an hungred, and they which were with him;
The saying was given as Jesus and His disciples were passing through a grainfield on the Sabbath, when the disciples plucked standing heads of wheat or ears of corn, rubbed them in their hands, and ate the kernels. The surrounding account also includes His healing of a withered hand, and the incident is one of special interest in Christ's life. The scribes and Pharisees had been watching and spying on all His actions and words to find cause to accuse Him, and they charged Jesus, the Lord of the Sabbath, and His disciples with breaking the Sabbath for gathering and eating the grain. The law permitted a hungry person to enter another person's field or vineyard and eat grain or fruit to satisfy hunger, so the disciples' taking and eating was within that provision and their hunger did not make it a violation of the Sabbath commandment.
To answer, Jesus appealed to what David did when himself hungry with his men in eating the showbread set apart to holy use and lawful only for priests. His question, Have ye not read, was a rebuke for ignorance of the Scriptures. If it was right for David to satisfy hunger with holy bread, it was right for the disciples to supply their need with grain on the sacred hours of the Sabbath. By this answer Christ repelled the charge and established the innocence of His disciples, declaring them guiltless and the accusation false, acquitting them by the very statutes they were accused of violating. The example proves that the service of God comes first and what is necessary for God's redeeming work is in accord with the Sabbath law. Jesus kept the Sabbath according to God's law rather than the rabbis' requirements and challenged Sabbath rules that misrepresented God.
He did this with a dignity He alone possesses as God in the flesh, in whom dwells all the fullness of the Godhead bodily with the divine and human united to act out the principles that govern heaven, covering His disciples with the shield of His own prerogatives as the One who made the Sabbath and is Lord of the Sabbath. The incident exposes the fallibility, foolishness, weakness, and blindness of human judgment. Despite unmistakable evidence that He was sent of God, the rulers took up a work prompted by the enemy to condemn the greatest Teacher, even charging the Maker and Lord of the Sabbath with Sabbath-breaking, as if they had put out their own eyes.