Matthew 12:7b - Mercy and Sacrifice.

I will have mercy, and not sacrifice. Mat 12:7b (KJV)

Jesus applied the principle of Hosea 6:6 to the Sabbath laws
(Matt. 12:7). Jesus showed the Pharisees that the Sabbath was a day for
mercy and rest, not for adding extra burdens to the lives of the
people. Eating grain while passing through fields was permitted by Old
Testament law (12:1; cf. Deut. 23:25). The fourth commandment (Exod.
20:8-11) set the Sabbath (seventh day) apart as a day to reflect on God's
work of creation and delight in the Lord (Isa. 58:13-14). This was an
example of what Jesus meant in saying that his yoke was easy (Matt.
11:29). This passage compared the heavy burdens imposed by the Pharisees
with the light burdens given by the Lord. . . . As in Matthew 9:13,
Jesus (12:7) once again cited Hosea 6:6. A heart of mercy and
compassion would recognize that meeting a person's needs was more important
than following every ritual element of Sabbath observance. [New Bible
Companion]

Ceremonial duties must give way to moral, and the natural, royal
law of love and self-preservation must take place of ritual
observances. This is quoted from <Hos. 6:6>. It was used
before, <Mt 9:13>,
in vindication of mercy to the souls of men; here, of mercy to
their bodies. The rest of the sabbath was ordained for man's good, in
favour of the body, <Deut. 5:14>. Now no law must be construed so as to
contradict its own end. If you had known what this means, had known what it
is to be of a merciful disposition, you would have been sorry that
they were forced to do this to satisfy their hunger, and would not
have condemned the guiltless. (Matthew Henry's Commentary)

Had you understood the great spiritual principle, which the
Scripture everywhere recognizes--that ceremonial observances must give way
before moral duties, and particularly the necessities of nature--ye
would have refrained from these complaints against men who in this
matter are blameless. [Jamieson, Fausset, And Brown Commentary]

What God desires far more than ritual sacrifice is kindness, the
spirit which knows no law other than that it must answer the call of
human need. . . . Jesus lays it down that the claim of human need must
take precedence of all other claims. The claims of worship, the
claims of ritual, the claims of liturgy are important but prior to any
of them is the claim of human need. [Barclay Commentary]

Sacrifices were in themselves of no value. They were a means,
and not an end. Their object was to direct men to the Saviour, and
thus to bring them into harmony with God. It is the service of love
that God values. When this is lacking, the mere round of ceremony is
an offense to Him. So with the Sabbath. It was designed to bring
men into communion with God; but when the mind was absorbed with
wearisome rites, the object of the Sabbath was thwarted. Its mere outward
observance was a mockery.  DA286,7

God is more interested in the heart than in empty outward
observances. [Wiersbe Expository Outlines]

God desires proper hearts far more than externals which have
become mere formalities. [Wycliffe Bible Commentary]

Our heart attitude toward God comes first.  Only then can we
properly obey and observe religious regulations and rituals.  [Life
Application SB]