One of the explicit teachings of the Bible is the importance of the words we speak. In this text God changes Abram’s name to Abraham and promises Abraham that he will become the father of many nations. “Abram” means “High Father” or “Patriarch.” “Abraham” means “Father of a Multitude.” Thus, God was arranging that every time Abraham heard or spoke his own name, he would be reminded of God’s promise.
Adam Clarke’s Commentary states it well: “God [associates] the patriarch more nearly to Himself, by thus imparting to him a portion of His own name,” noting God added this to Abraham “for the sake of dignity.”
The principle: Let God’s words, which designated His will and promise for your life, become as fixed in your mind and as governing of your speech as God’s changing Abraham’s name was in shaping his concept of himself. Do not “name” yourself anything less than God does.