What is the meaning of 'I desire mercy and not sacrifice'? I've been reading through the book of Matthew, and in chapter 9 I came across verse 13. It's when Jesus was answering the Pharisees after they asked Him why He ate with the tax collectors and sinners:


  13: But go ye and learn what this meaneth, I desire mercy, and not sacrifice, for I came not to call the righteous, but sinners.


I didn't give it much of a thought until I came to chapter 12 verse 7. Here again Jesus was answering the Pharisees too after they asked Him why His disciples were plucking and eating the ears of grains on a Sabbath.


  7: But if ye had known what this meaneth, I desire mercy, and not sacrifice, ye would not have condemned the guiltless. 


And the first part really hit me - "if ye had known what this meaneth". 

I did a Bible search for the phrase and found Hosea 6:6


  For I desired mercy, and not sacrifice; and the knowledge of God more than burnt offerings.


Can someone please explain to me in a very simple way what the phrase means "I desire mercy, and not sacrifice" and why Jesus was telling that to the pharisees.

Why does he use the specific word mercy?

Checking the meaning of the word at google it says:


  Compassion or forgiveness shown toward someone whom it is within one's power to punish or harm.
Jesus was with little doubt alluding to the passage in Hosea.

See also Isaiah 1:11-17 (21st Century KJV)


  11: To what purpose is the multitude of your sacrifices unto me? saith the Lord: I am full of the burnt offerings of rams, and the fat of fed beasts; and I delight not in the blood of bullocks, or of lambs, or of he goats.
  12: When ye come to appear before me, who hath required this at your hand, to tread my courts?
  13: Bring no more vain oblations; incense is an abomination unto me; the new moons and sabbaths, the calling of assemblies, I cannot away with; it is iniquity, even the solemn meeting.
  14: Your new moons and your appointed feasts my soul hateth: they are a trouble unto me; I am weary to bear them.
  15: And when ye spread forth your hands, I will hide mine eyes from you: yea, when ye make many prayers, I will not hear: your hands are full of blood.
  16: Wash you, make you clean; put away the evil of your doings from before mine eyes; cease to do evil;
  17: Learn to do well; seek judgment, relieve the oppressed, judge the fatherless, plead for the widow.


What Jesus was saying was if the Pharisees knew God and understood what really mattered to Him, they would not put such overemphasis on rules about such things as ritual cleanliness and restrictive Sabbath observance.