Catechism of the Catholic Church

After the patriarchs, God formed Israel as his people by freeing them from slavery in Egypt. He established with them the covenant of Mount Sinai and, through Moses, gave them his law so that they would recognize him and serve him as the one living and true God, the provident Father and just judge, and so that they would look for the promised Savior. (2060, 2574, 1961)