Blessed are the peacemakers: for they shall be called the children of God. The peace-makers - Ειρηνη, peace, is compounded of ειρειν (εις) ἑν, connecting into one: for as War distracts and divides nations, families, and individuals, from each other, inducing them to pursue different objects and different interests, so Peace restores them to a state of unity, giving them one object, and one interest. A peace-maker is a man who, being endowed with a generous public spirit, labors for the public good, and feels his own interest promoted in promoting that of others: therefore, instead of fanning the fire of strife, he uses his influence and wisdom to reconcile the contending parties, adjust their differences, and restore them to a state of unity. As all men are represented to be in a state of hostility to God and each other, the Gospel is called the Gospel of peace, because it tends to reconcile men to God and to each other. Hence our Lord here terms peace-makers the children of God: for as he is the Father of peace, those who promote it are reputed his children. But whose children are they who foment divisions in the Church, the state, or among families? Surely they are not of that God, who is the Father of peace, and lover of concord; of that Christ, who is the sacrifice and mediator of it; of that Spirit, who is the nourisher and bond of peace; nor of that Church of the Most High, which is the kingdom and family of peace.
St. Clement, Strom. lib. iv. s. 6, in fin. says, that "Some who transpose the Gospels add this verse: Happy they who are persecuted by justice, for they shall be perfect: happy they who are persecuted on my account, for they shall have a place where they shall not be persecuted."