One of the reasons we need to praise God is because He makes and keeps covenants with mankind. We should praise Him because of His generous providence. We need to praise Him because He is the King of heaven and of earth. And we should praise Him because He is our Creator.
When we pray to God we need to exalt His name. We should praise Him for the blessings He has given both to us and to our ancestors. And we need to acknowledge that He alone is God.