The mercy passage
Mat 12: 12 At that time Jesus went through the cornfields on the sabbath; his disciples were hungry, and they began to pluck heads of grain and to eat. 2 When the Pharisees saw it, they said to him, ‘Look, your disciples are doing what is not lawful to do on the sabbath.’ 3 He said to them, ‘Have you not read what David did when he and his companions were hungry? 4 He entered the house of God and ate the bread of the Presence, which it was not lawful for him or his companions to eat, but only for the priests. 5 Or have you not read in the law that on the sabbath the priests in the temple break the sabbath and yet are guiltless? 6 I tell you, something greater than the temple is here. 7 But if you had known what this means, “I desire mercy and not sacrifice”, you would not have condemned the guiltless. 8 For the Son of Man is lord of the sabbath.’ (NRSV)
Matthew 12:7: Is this a quote from the well-known passage in Micah that speaks about practicing mercy and walking humbly with thy God?
This idea is understandable as people in general don’t know a lot of quotes from the Old Testament and the passage from Micah is one of those text verses that some use as a motto for life. It features in framed pictures on walls, just like John’s “God is love” and “home sweet home”. Whenever people hear about love, they will make the connection. The same with Micah, whenever mercy features, someone is bound to hear the Micah bell ring. This can be useful in a complementary way, but…
The short answer is, no. The Lord quotes from the prophet Hosea (6:6),
6 For I desired mercy, and not sacrifice, and the knowledge of God more than burnt offerings. (Geneva 1599 ed.)
Apparently this was an important message to take to heart, as Jesus had said more or less the same thing in Matthew 9:13.
13 But go ye and learn what this is, I will have mercy, and not sacrifice: for I am not come to call the righteous, but the sinners to repentance.
So although Jesus quotes from Hosea and not from Micah, the verse from the latter could be said to represent a similar spirit.
8 He hath showed thee, O man, what is good, and what the Lord requireth of thee: surely to do justly, and to love mercy, and to humble thyself, to walk with thy God.
A quick comparison shows that both passages say that mercy is important, so in that sense there is similarity in thought. Walking with God could be said to imply also some knowledge of God.
Otherwise, Jesus/Hosea emphasizes mercy versus sacrifice and the importance of the knowledge of God versus offerings. As you can see, at a linguistic level the Micah passage contains only one of the four points that Jesus mentions.
However, whatever the origins of the quote, we could all do with more mercy, justice and knowledge of God in our lives. This world should be a better place as a result.