Matthew 5:3-12 lists eight Beatitudes that were spoken of by Jesus. Jesus said, “Blessed are the peacemakers: for they shall be called the children of God.” (Matthew 5:9)

To be blessed, one must have the attitude of being a peacemaker.

What does it mean to be a peacemaker and why shall the peacemakers be called the children of God? Before Jesus’ birth, the prophecy by Isaiah entitled Jesus to be The Prince of Peace (Isaiah 9:6). At His birth, the heavenly angelic choir sang, ‘peace’ on earth (Luke 2:14). It is possible to have peace on earth, because The Prince of Peace came to earth, to do the will of God the Father, which was to reconcile mankind back to God by redeeming mankind from death and sin. He accomplished this on the Cross, from where he affirmed that God’s work of redeeming mankind to and for Himself was finished. In other words, Jesus’ mission was a mission of restoring peace; a peace that passeth all understanding (Philippians 4:7) and all who put their trust in Jesus with their minds fixed on Him will be kept in perfect peace (Isaiah 26:3). Those who have believed in Jesus are covenanted to have a life of peace (Malachi 2:5) as God’s royal priests (1 Peter 2:9). God commands that the life of a priest must be one of peace and uprightness, turning many from sins (iniquities) with the message of God’s Love (Malachi 2:6-7); a love so great that He gave us His only begotten Son, to pay the wages of our sins (which is death), by His very own life (John 3:16). The God given responsibility of a priest is to be a messenger of the Lord (Malachi 2:7); a messenger with the message of peace. In other words, to be a priest is to be a peacemaker, turning many from sin and reconciling mankind to God for we have been given the ministry of reconciliation (2 Corinthians 5:18). And all who are peacemakers, are in essence, emulating the very mission of Jesus Christ, just as a child imitates the character of a parent and in this sense are rightfully called the children of God. God is a God of peace who works to make all perfect (blameless without sin) through the covenant of the blood of His dear Son, Jesus Christ (Hebrew 13:20-21), and all who are peacemakers imitate God the Father and are thereby blessed as His children.

Matthew 5:9 (KJV)
9 Blessed are the peacemakers: for they shall be called the children of God.

2 Corinthians 5:16-21 (KJV)
16 Wherefore henceforth know we no man after the flesh: yea, though we have known Christ after the flesh, yet now henceforth know we him no more.
17 Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
18 And all things are of God, who hath reconciled us to himself by Jesus Christ, and hath given to us the ministry of reconciliation;
19 To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation.
20 Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ’s stead, be ye reconciled to God.
21 For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.