Listen and don’t add
Moses reminds Israel of their past rebellions and sins because they are getting ready for battle of the promised land and they needed to be obedient to the Lord.
Another warning about adding to the word of God also appears in the book of Revelation.
Revelation 22: 18[i]For I testify to everyone who hears the words of the prophecy of this book: If anyone adds to these things, [j]God will add to him the plagues that are written in this book; 19and if anyone takes away from the words of the book of this prophecy, God[k] shall take away his part from the [l]Book of Life, from the holy city, and from the things which are written in this book.
Man has a nasty habit of adding or taking away from the word of God.
Have you ever added to the word about requirements for salvation?
Blessings