Mercy is not showered promiscuously upon mankind, wrote Elder Bruce R. McConkie, “except in the general sense that it is manifest in the creation and peopling of the earth and in the granting of immortality to all men as a free gift” (Mormon Doctrine, p. 484). Rather, mercy is granted (because of the grace, love, and condescension of God), as it is with all blessings, to those who comply with the law upon which its receipt is predicated (see D&C 130:20-21).
That law is the law of righteousness: those who sow righteousness reap mercy (see Hosea 10:12). There is no promise of mercy to the wicked; rather, as stated in the Ten Commandments, the Lord promises to show mercy unto thousands of them that love him and keep his commandments (see Exodus 20:6; Daniel 9:4; D&C 70:18).