Blessed are the peacemakers, for they will be called children of God. (Matthew 5:9)
I've never thought about the difference between ‘peacemaking’ and ‘peacekeeping’. Dr. King's point that unity is not simply peace rings true. "Peace can be reduced to avoiding engaging in open conflict and yet still be emotionally distant and cold."
Instead is a fruit of humility. Just as it's said that the more you know the more you realize what you don't know, "it is a sign of wisdom when a person admits that the way they see things (within the "bounds" of truth) may not be correct." As we strive to learn The Truth, true unity and peacemaking is achieved when we mutually provide grace and charity to those who disagree by realizing that my understanding may be incomplete and my judgments may be wrong on specific issues.
"Who is wise and understanding among you? Let them show it by their good life, by deeds done in the humility that comes from wisdom. But if you harbor bitter envy and selfish ambition in your hearts, do not boast about it or deny the truth. Such “wisdom” does not come down from heaven but is earthly, unspiritual, demonic. For where you have envy and selfish ambition, there you find disorder and every evil practice. But the wisdom that comes from heaven is first of all pure; then peace-loving, considerate, submissive, full of mercy and good fruit, impartial and sincere. Peacemakers who sow in peace reap a harvest of righteousness." (James 3:13-18)
(Roy King - Unity & Purity)