This is a summation of the Christian message to the world. Those who understand the righteousness of God will see their need for His mercy, which is found only in Jesus Christ. However, there can be no mercy until the hard soil of the heart has been broken up by the plow of the Law (see Rom. 7:7,13). It prepares the heart for the seed of the gospel (see Gal. 3:24).
“There must be plowing before there is sowing if there is to be reaping after the sowing!” Charles Spurgeon
Hosea 10:12 Sow for yourselves righteousness; Reap in mercy; Break up your fallow ground, For it is time to seek the Lord, Till He comes and rains righteousness on you.