"Give thanks to the Lord; call upon His name. Rabbi Yosei bar Chalafta said to Rabbi Yishmael his son, 'If you seek to see the Divine Presence in this world, engage in Torah in the Land of Israel, as it is said, "Seek the Lord and His strength; seek His presence continually" (Psalms 105:4). Remember His wondrous deeds that He has done.' Rabbi Elazar said, 'For it is through Isaac that offspring shall be named for you' (Genesis 21:12).
Whoever is named after Isaac is considered as if he were Isaac, as it is said, "For it is through Isaac." Rabbi Yudan said, 'Only partially and not completely, as it is said, "In Isaac" and not "in all of him." Whoever acknowledges the two worlds [this world and the world to come] is called your offspring, but whoever does not acknowledge the two worlds is not called your offspring.'"