Great Faith in a Great God

Now the LORD had said to Abram: "Get out of your country, From your family And from your father's house, To a land that I will show you. I will make you a great nation; I will bless you And make your name great; And you shall be a blessing. I will bless those who bless you, And I will curse him who curses you; And in you all the families of the earth shall be blessed." 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. Then Abram took Sarai his wife and Lot his brother's son, and all their possessions that they had gathered, and the people whom they had acquired in Haran, and they departed to go to the land of Canaan. So they came to the land of Canaan. Abram passed through the land to the place of Shechem, as far as the terebinth tree of Moreh. And the Canaanites [were] then in the land. (Genesis 12:1-6)After these things the word of the LORD came to Abram in a vision, saying, "Do not be afraid, Abram. I [am] your shield, your exceedingly great reward." But Abram said, "Lord GOD, what will You give me, seeing I go childless, and the heir of my house [is] Eliezer of Damascus?" Then Abram said, "Look, You have given me no offspring; indeed one born in my house is my heir!" And behold, the word of the LORD [came] to him, saying, "This one shall not be your heir, but one who will come from your own body shall be your heir." Then He brought him outside and said, "Look now toward heaven, and count the stars if you are able to number them." And He said to him, "So shall your descendants be." And he believed in the LORD, and He accounted it to him for righteousness. (Genesis 15:1-6 NKJV)
And the LORD visited Sarah as He had said, and the LORD did for Sarah as He had spoken. For Sarah conceived and bore Abraham a son in his old age, at the set time of which God had spoken to him. And Abraham called the name of his son who was born to him--whom Sarah bore to him--Isaac. ... Now Abraham was one hundred years old when his son Isaac was born to him. And Sarah said, "God has made me laugh, [and] all who hear will laugh with me." She also said, "Who would have said to Abraham that Sarah would nurse children? For I have borne [him] a son in his old age." (Genesis 21:1-3, 5-7 NKJV)