1. Or have ye not read in the law, how that on the sabbath days the priests in the temple profane the sabbath, and are blameless?
2. in this place is one greater than the temple
3. But if ye had known what this meaneth, I will have mercy, and not sacrifice, ye would not have condemned the guiltless.

1. The sabbath was made for man, and not man for the sabbath:

1. second sabbath after the first,
2. rubbing them in their hands.

Issues

1. Exodus 20:8-11
2. Second Sabbath after the First (Luke 6:1)
   • The first of the seven sabbaths between Passover and Pentecost
   • Priestly liturgical observances mentioned in Leviticus 23:15,16; Deuteronomy 16:9,10 and others
   • Note the relationship between Passover and Easter
     • Passover begins the 14th day of Nisan, the first lunar month of the Jewish calendar (starting with a new crescent moon, placing the Passover at full moon)  
     • The Council of Nicea (325) set Easter Day as the first Sunday after the 14th day of the lunar month (full moon) that falls on or after the vernal equinox (Mar. 21), unless that full moon falls on a Sunday, in which case Easter is the following Sunday.
3. "what David did"  (Matthew 12:3)
   • 1 Samuel 21:1-6
   • And necessity was a sufficient plea for his transgressing the law in a higher instance. John Wesley Notes
4. "the priests in the temple profane the sabbath, and are blameless" (Matthew 12:5)
   • That is, do their ordinary work on this, as on a common day, cleansing all things, and preparing the sacrifices. 
     John Wesley Notes
   • When the priests do God's service on the sabbath day, they do not break the law: much less does the Lord of the Sabbath break the sabbath.  Geneva Bible Notes
5. "in this place is one greater than the temple"  (Matthew 12:6)
   • If therefore the Sabbath must give way to the temple, much more must it give way to me.  John Wesley Notes
6. "I will have mercy, and not sacrifice" (Matthew 12:7)
   • Event 055: Eating with Sinners at Matthew's House
   • Hosea 6:5-7
7. "The sabbath was made for man, and not man for the sabbath"  (Mark 2:27)
   • And therefore must give way to man's necessity.  John Wesley Notes
   • That he might have the seventh part of his whole time to devote to the purposes of bodily rest and spiritual exercises.
      Adam Clarke Commentary
   • As the Sabbath was made for the whole human race, they have a right to its rest and privileges. This right does not come from men, but from God, and its exercise is essential to their present and future good.  Family Bible Notes
8. " the Son of man is Lord also of the sabbath"  (Luke 6:5)
   • -This certainly implies, that the Sabbath was an institution of great and distinguished importance; it may perhaps also refer to that signal act of authority which Christ afterward exerted over it, in changing it from the seventh to the first day of the week.  John Wesley Notes
   • -In what sense now is the Son of man Lord of the sabbath day? Not surely to abolish it--that surely were a strange lordship, especially just after saying that it was made or instituted for MAN--but to own it, to interpret it, to preside over it, and to ennoble it, by merging it in the "Lord's Day" (Re 1:10), breathing into it an air of liberty and love necessarily unknown before, and thus making it the nearest resemblance to the eternal sabbatism.  Jamieson-Fausset-Brown Commentary
   •  Because the Sabbath is made for humanity, the Lord of humanity is the Lord of the Sabbath. Observe, is the Lord of the Sabbath. He does not, then, abolish it, but has the right to make any change in it, in the interest of mankind, that seems to him wise. Neither Moses, nor any other mortal, ever claimed to be Lord of the Sabbath. This is a declaration of Divinity. People's New Testament Commentary