It is in Scripture the classic picture of true faith.

Abraham was called out of Ur of the Chaldees,
Gen 11:31

“1 Now Yahweh said to Abram, “Get out of your country, and from your relatives, and from your father’s house, to the land that I will show you. 2 I will make of you a great nation. I will bless you, and make your name great. You will be a blessing.” ”
Gen 12:1-2

The Lord does not tell Abram where he will go. He makes it plain that the Lord Himself will make Abram’s name “great,” and “a great nation” will come from Him, and God Himself will bless him. Then it hits.

“So Abram went, as Yahweh had spoken to him. Lot went with him. Abram was seventy-five years old when he departed out of Haran.”
Gen 12:4

Seventy-five years old! That is more than a little late for starting a tribe of anything, much less a great nation. Still, Abram goes where he is told and is promised Palestine in the following chapters. Abram had not seen any results yet, but he believed and followed.

God appeared to Abram again in Genesis 15

God tells him, “Don’t be afraid, Abram. I am your shield, your exceedingly great reward.” Gen 15:1b. The years have past. Abram protests, “what will you give me, seeing I go childless,” but God assures him that from his own body he will have descendants as numerous as the stars of heaven, Gen 15:4-5.

Of Abraham it says, “He believed in Yahweh, and
he reckoned to him for righteousness.”
Gen 15:6

All he has is the prophecies.

“He said to him, “I am Yahweh who brought you out of Ur of the Chaldees, to give you this land to inherit it.” ”
Gen 15:7

In the following verses God enters into a formal covenant with Abram, and prophecies are extended to 400 years of slavery in a foreign land for his yet unborn progeny, before they inherit this land.

Mere words of the future. This might seem
pretty thin to many.

However, Abram trusted that God could do what He said.

“19 Without being weakened in faith, he didn’t consider his own body, already having been worn out, (he being about a hundred years old), and the deadness of Sarah’s womb. 20 Yet, looking to the promise of God, he didn’t waver through unbelief, but grew strong through faith, giving glory to God, 21 and being fully assured that what he had promised, he was able also to perform.”
Rom 4:19-21

There were yet more trials.

A false start with a son by a slave woman at age 86, Gen 16:16. But God said no! The son of promise would be through his wife Sarai. Then finally came the son by Sarah in Isaac. Then one more test in Genesis 22 to see if Abraham was willing to sacrifice this one and only son.

All of these were tests of faith in God’s Prophetic Word

Believing what God says in prophecy does matter! It is an ethical matter.

Scriptures are from the World English Bible (WEB), a copyright free revision
of the original ASV American Standard Version 1901