“Abraham’s removal out of his country, out of Ur first and afterwards out of Haran, in compliance with the call of God: So Abram departed; he was not disobedient to the heavenly vision, but did as he was bidden, not conferring with flesh and blood (Gal. 1:15,16). His obedience was speedy and without delay, submissive and without dispute; for he went out, not knowing whither he went (Heb. 11:8), but knowing whom he followed and under whose direction he went.” Matthew Henry
God has spoken to every Christian—to go into the entire world and preach the gospel to every creature. We must not be disobedient to the heavenly vision.
Genesis 12:4 So Abram departed as the Lord had spoken to him, and Lot went with him. And Abram was seventy-five years old when he departed from Haran.