“And he slew all the priests of the high places that were there upon the altars, and burned men’s bones upon them, and returned to Jerusalem. And the king commanded all the people, saying, Keep the passover unto the LORD your God, as it is written in the book of this covenant. Surely there was not holden such a passover from the days of the judges that judged Israel, nor in all the days of the kings of Israel, nor of the kings of Judah;” (2 Kings 23:20-22, KJV)
The book of the covenant contains all the promises and conditions of God’s relationship with His people, Israel. The passover was the celebration which marked God’s deliverance of His people from Egypt. He delivered them from Egypt because of the covennant He made with Abraham, Isaac and Jacob to give their seed the land of Canaan as an inheritance. Keeping the passover served as a constant reminder of how God had delivered His people so that from generation to generation, they would not forget.
The Bible is the book of the covenant. The words contain therein serve as a reminder of all that God has done for us, so that we too, will not forget.