When Christ was born, the angels gave glory to God for His birth that would bring peace on earth to those that would receive His mercy.

"And suddenly there was with the angel a multitude of the heavenly host praising God, and saying, Glory to God in the highest, and on earth peace, good will toward men [“to those on whom his favor rests”]." - Luke 2:13-14 KJV

The birth of Jesus came with His purpose to give His life for the salvation of the world. He came to restore the peace between us and Himself, that had been shattered by sin.

"And, having made peace through the blood of his cross, by him to reconcile all things unto himself; by him, I say, whether they be things in earth, or things in heaven." - Colossians 1:20 KJV

Isaiah foretold of Jesus’ birth, revealing His identity as the Father – the mighty God – that was born to bring peace through the establishment of His kingdom on earth. Jesus would bring His kingdom by the gospel. HE would receive the judgment and justice for OUR sin, once and for all, by His suffering and death on the cross. Buried and resurrected, He accomplished victory and everlasting peace.

"For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace. Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even for ever. The zeal of the LORD of hosts will perform this." - Isaiah 9:6-7 KJV

The zeal of the LORD – God’s love for mankind – performed this humbling of Himself to redeem us from sin and death. God’s passion for His beloved caused Him His great sacrifice. (Hebrews 2:14-15, Philippians 2:7-8, Acts 20:28).

We enter His kingdom by the new birth – being born again of water and of the Spirit. (John 3:5). This new birth into His kingdom is called the gospel of peace, because it brings peace between us and Jesus.

This is what Peter preached, beginning on the Day of Pentecost.

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call." - Acts 2:38-39 KJV

Those that obey this gospel of peace find true peace and the favor of God.