Albert Barnes Commentary Luke 1:32

"He shall be great, and shall be called the Son of the Most High: and the Lord God shall give unto him the throne of his father David:" — Luke 1:32 (ASV)

He shall be great. This passage undoubtedly refers to Isaiah 9:6-7. By His being great is meant that He will be distinguished or illustrious—great in power, in wisdom, in dominion, on earth and in heaven.

Shall be called. This means the same as saying He shall be the Son, and so on. The Hebrews often used this form of speech (Matthew 21:13).

The Highest. God, who is infinitely exalted, is called the Highest because He is exalted over all His creatures on earth and in heaven (Mark 5:7).

The throne. This refers to the kingdom, or it means that God will appoint Him as the lineal successor of David in the kingdom.

His father David. David is called His father because Jesus was lineally descended from him (Matthew 1:1). The promise to David was that there should not fail a man to sit on his throne, or that his throne would be perpetual, and this promise was fulfilled by exalting Jesus to be a Prince and a Saviour, and the perpetual King of His people.