It was unashamed dislike of God’s mercy for the heathen that prompted Jonah to run from preaching to Nineveh. Jonah, like many in ancient Israel wanted to reserve God mercy for himself and his own people.
If we do not appreciate the extent of God’s mercy, we will not participate in the extension of God’s Kingdom. Study the cross of Christ; it is there that we see the greatness of God’s mercy. First, in that He saves so obnoxious and rebellious sinners. Jesus Christ died for those who pursued him to death (John 19:6). Second, that He saves so generally and unreservedly. John tells us that the gospel is not for the Jew only “but for the whole world” (1 John 2:2). Third, that He saves at such a high cost; the death of His Son. “God gave,” not anything or anyone, but His “only begotten Son” (John 3:16).
Many are happy to receive God’s mercy but reluctant to share it; Jesus said “freely ye received, freely give” (Matthew 10:8).
“Oh the supererogating mercy of God that is not only content to do what is barely sufficient for our salvation; but, over and above, adds, what may be most expressive of his own affection, John 3:16. God so loved the world … How, what, to save it only? No: he so loved it that he gave his only begotten Son to save it!” —Ezekiel Hopkins (Works 1:587).