John Gill Commentary Luke 19:38

"saying, Blessed [is] the King that cometh in the name of the Lord: peace in heaven, and glory in the highest." — Luke 19:38 (ASV)

Saying, blessed be the King
The King Messiah, the King of Israel, the son of David, the Christ of God; so the Ethiopic version adds, "blessed be the King of Israel"; they sung their "Hosannas" to him, as the other evangelists say:

that comes in the name of the Lord; (See Gill on Matthew 21:9)

peace in heaven ;
all heavenly peace and prosperity attend him; or let peace be made with God in heaven, by the Prince of Peace on earth, for sinful men:

and glory in the highest ;
glory be given to God for peace, life, and salvation by his son; and that in the highest heavens, by the angels there, as well as by men on earth, and in the highest notes and strains.