'Blessed are the peacemakers, for they shall be called sons of God.' (Matthew 5:9)
But what is involved in 'making peace'? Is it merely 'making nice'? We are, unfortunately, familiar with the term 'wage war.' In the temporal realm we presume that peace is simply what happens when we stop waging war.
Yet in the spiritual realm, in the reality of man's heart, it is peace that needs to be waged. Long after outward hostilities cease, conflict still rages. Scripture tells us that peace is not our natural state, that we do not need to 'wage war' because we are already at war, both with God and with man. Warfare is our natural inclination, both temporally and spiritually.
Jeremiah warned Israel "They have spoken falsely of the Lord and have said 'He will do nothing; no disaster will come upon us.'" He chastised the prophets and priests -- Israel's spiritual leaders -- because they 'have healed the wound of my people lightly (superficially) saying 'Peace, peace' when there is no peace.' (Jeremiah 5:9 and 6:14). Israel merely claimed peace without waging it.
Similarly in the church today we cannot merely proclaim peace. It must be waged, it must be striven for. In Ephesians we are told to 'be diligent to preserve the unity of the Spirit in the bond of peace...speaking the truth in love' (4:3, 4:14). The terms used here imply a military striving to prevail in the warfare that would seek the destruction of peace. If conflict is the frustration of any goal or desire (Ken Sande, The Peacemaker), it could be something simple, in which case 'love covers a multitude of sins.' But it could create resentment and bitterness.
In that case, Jesus tells us what to do to 'wage peace.' In Matthew 18, we are told to go to our offending brother and report the matter. If he listens, you win your brother. If not, take two or three more. If he won't listen to them, take it to the church. If he won't listen to the church, put him out of it. Jesus' method is certainly not passive -- in which the conflict (breach of the peace) is ignored, hidden or glad-handed away -- but is assertive, addressing the conflict head on and waging peace upon it.
Growth with God, and growth between men, does not come by claiming peace where there is none. Claiming peace with God prematurely or on the wrong grounds leads to damnation. Claiming peace with men prematurely or on the wrong grounds perpetuates warfare and conflict. Especially in conflict between men, growth happens when the causes of that conflict are recognized, addressed and resolved.
'Waging peace' is not easy. Sometimes it is not pleasant. It is certainly not 'making nice.' But in contrast to a superficial truce -- one that terminates the gunfire but perpetuates the anger, the difficulty and hard work of 'waging peace.' accomplishes a unity that is truly in the Spirit.