The prophet who spoke extensively about the restoration of Israel and the coming of the Messiah was

The prophet who spoke extensively about the restoration of Israel and the coming of the Messiah was Malachi. Malachi was the last prophet in the Old Testament, and his book contains prophecies about a future restoration of Israel and the coming of the Messiah.
Malachi begins by addressing the people of Israel and expresses God's love for them. He then calls out the people's sins and exhorts them to return to the Lord with sincerity and repentance.
In Malachi 3:1, he prophesies about the coming of the Messiah, saying, "See, I will send my messenger, who will prepare the way before me. Then suddenly the Lord you are seeking will come to his temple; the messenger of the covenant, whom you desire, will come." This verse foretells the coming of John the Baptist, who prepared the way for Jesus Christ, the Messiah.
Malachi also speaks about the restoration of Israel. In Malachi 4:5-6, he says, "See, I will send the prophet Elijah to you before that great and dreadful day of the Lord comes. He will turn the hearts of the parents to their children, and the hearts of the children to their parents." This prophecy refers to the future restoration and reconciliation of families and the turning of hearts towards God.
Overall, Malachi's prophecies about the restoration of Israel and the coming of the Messiah are significant in the context of the Old Testament. They provide hope and anticipation for the fulfillment of God's promises and the eventual redemption of His people.