Genesis 12:1-5
Now the LORD had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father’s house, unto a land that I will shew thee: And I will make of thee a great nation, and I will bless thee, and make thy name great; and thou shalt be a blessing: And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed. So Abram departed, as the LORD had spoken unto him; and Lot went with him: and Abram was seventy and five years old when he departed out of Haran. And Abram took Sarai his wife, and Lot his brother’s son, and all their substance that they had gathered, and the souls that they had gotten in Haran; and they went forth to go into the land of Canaan; and into the land of Canaan they came.
Genesis 18:1-5,11-19
And the LORD appeared unto him in the plains of Mamre: and he sat in the tent door in the heat of the day; And he lift up his eyes and looked, and, lo, three men stood by him: and when he saw them, he ran to meet them from the tent door, and bowed himself toward the ground, And said, My Lord, if now I have found favour in thy sight, pass not away, I pray thee, from thy servant: Let a little water, I pray you, be fetched, and wash your feet, and rest yourselves under the tree: And I will fetch a morsel of bread, and comfort ye your hearts; after that ye shall pass on: for therefore are ye come to your servant.
Now Abraham and Sarah were old and well stricken in age; and it ceased to be with Sarah after the manner of women. Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also? And the LORD said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old? Is any thing too hard for the LORD? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son. Then Sarah denied, saying, I laughed not; for she was afraid. And he said, Nay; but thou didst laugh.
And the men rose up from thence, and looked toward Sodom: and Abraham went with them to bring them on the way. And the LORD said, Shall I hide from Abraham that thing which I do; Seeing that Abraham shall surely become a great and mighty nation, and all the nations of the earth shall be blessed in him?
For I know him, that he will command his children and his household after him, and they shall keep the way of the LORD, to do justice and judgment; that the LORD may bring upon Abraham that which he hath spoken of him.
I find such comfort in those words ‘ for I know him’. God had led and Abraham had followed. God knew Abraham would be faithful no matter what.