When you have eaten your fill, you shall bless YHVH your God for the good land that He has given you. (Devarim 8:10)
These words are the explicit source for the commandment of Birkat haMazon – blessing God after eating a meal. There are several blessings in the Birkat haMazon:
1.HaZan – praise for God, who sustains the world;
2.Birkat Ha’Aretz – thanks to God for everything, focusing on the Land of Israel;
3.Boneh Yerushalayim – petition to protect and rebuild Jerusalem;
4.HaTov vehaMeitiv – general praise and thanks for God.
In addition, when three or more men eat together, the Birkat haMazon is prefaced by the invitation known as Zimun. The Gemara (Berakhot 48b) expounds: