Abraham appears to be the first man that God communicated with after Adam sinned and was cast out of the garden of Eden. Their initial encounter is recorded in Genesis 12:1-3. It states, “Now the LORD said to Abram, ‘Go from your country and your kindred and your father’s house to the land that I will show you. And I will make of you a great nation, and I will bless you and make your name great, so that you will be a blessing. I will bless those who bless you, and him who dishonors you I will curse, and in you all the families of the earth shall be blessed.’” Later, Abraham questioned God’s faithfulness and was challenged to believe something that seemed impossible. Genesis 15:1-6 states:

After these things the word of the Lord came to Abram in a vision: “Fear not, Abram, I am your shield; your reward shall be very great.” But Abram said, “O Lord God, what will you give me, for I continue childless, and the heir of my house is Eliezer of Damascus?” And Abram said, “Behold, you have given me no offspring, and a member of my household will be my heir.” And behold, the word of the Lord came to him: “This man shall not be your heir; your very own son shall be your heir.” And he brought him outside and said, “Look toward heaven, and number the stars, if you are able to number them.” Then he said to him, “So shall your offspring be.” And he believed the Lord, and he counted it to him as righteousness.

The King James Version of the Bible indicates that Abraham “believed in the LORD.” The Hebrew word that is translated believed, âman (aw-man´) means “to stand firm, to trust, to be certain, to believe in” (H539). Âman is translated faithful in Numbers 12:7 where God said that Moses had been faithful to him and in Deuteronomy 7:9 where it says, “Know therefore that the LORD your God is God, the faithful God who keeps covenant and steadfast love with those who love him and keep his commandments, to a thousand generations, and repays to their face those who hate him, by destroying them.”

Faith and believing are linked together in the New Testament in the book of Hebrews. In the eleventh chapter of Hebrews, the author starts out by defining faith and then, goes on to give numerous examples of what faith looked like in the lives of people in the Old Testament who had believed in God. Hebrews 11:1 states, “Now faith is the assurance of things hoped for, the conviction of things not seen,” and then, the author stated, “By faith Abraham, when he was tested, offered up Isaac, and he who had received the promises was in the act of offering up his only son, of whom it was said, ‘Through Isaac shall your offspring be named.’ He considered that God was able even to raise him from the dead, from which, figuratively speaking, he did receive him back” (Hebrews 11:17-19).

Abraham’s faith was tested by his obedience to God’s command to offer his son as a sacrifice even though it seemed to contradict the promise that God had made about blessing all the families of the earth through his offspring Isaac (Genesis 12:3, 15:4). When Isaac asked his father where that lamb for the burnt offering was (Genesis 22:7), Abraham answered, “God will provide for himself the lamb for the burnt offering” (Genesis 22:8). Abraham understood that there was a need for a sacrifice for sin and believed that God would provide for that need himself. During his institution of the Lord’s Supper, after he had taken the cup and given thanks, Jesus told his disciples, “Drink of it all of you, for this is my blood of the covenant, which is poured out for many for the forgiveness of sins” (Matthew 26:27-28).

On numerous occasions, Jesus warned his disciples that he was going to be killed, but assured them that he would be raised him from the dead (Matthew 20:19). After Jesus’ resurrection, an angel appeared to Mary Magdalene and Jesus’ mother Mary and told them, “Do not be alarmed. You seek Jesus of Nazareth, who was crucified. He has risen; he is not here. See the place where they laid him. But go, tell his disciples and Peter that he is going before you to Galilee. There you will see him, just as he told you” (Mark 16:6-7). Mark goes on to say:

Now when he rose early on the first day of the week, he appeared first to Mary Magdalene, from whom he had cast out seven demons. She went and told those who had been with him, as they mourned and wept. But when they heard that he was alive and had been seen by her, they would not believe it. (Mark 16:9-11)

Mark indicated that Jesus’ disciples would not believe that he was alive. In other words, those who had been with Jesus when he instituted the Lord’s Supper, and were told numerous times that he would come back to life the third day after he was crucified (Matthew 20:19), refused to believe that he had actually done what he said he would.

Mark’s account of Jesus’ resurrection emphasized the point that some people believed and some did not when they were told about Jesus’ resurrection. Mark stated, “After these things he appeared in another form to two of them, as they were walking in the country. And they went back and told the rest, but they did not believe him” (Mark 16:12-13). It was not only Mary’s testimony that wasn’t believed, but also the testimony of two others to whom Jesus had appeared. The Greek word that is translated did not believe, apisteo (ap-is-teh´-o) means “to betray a trust, be unfaithful” and by implication to “disobey…i.e. without faith in God and Christ (Mark 16:16; Romans 3:3); to break one’s faith, to prove false (2 Timothy 2:13)” (G569). A person that is apisteo is an unbeliever (G571).

Paul considered the possibility that the disciples and other Jews’ unbelief could nullify the effect of Christ’s sacrifice on the cross. Paul argued:

Then what advantage has the Jew? Or what is the value of circumcision? Much in every way. To begin with, the Jews were entrusted with the oracles of God. What if some were unfaithful? Does their faithlessness nullify the faithfulness of God? By no means! Let God be true though every one were a liar, as it is written,

“That you may be justified in your words,
    and prevail when you are judged.”

But if our unrighteousness serves to show the righteousness of God, what shall we say? That God is unrighteous to inflict wrath on us? (I speak in a human way.) By no means! For then how could God judge the world? But if through my lie God’s truth abounds to his glory, why am I still being condemned as a sinner? And why not do evil that good may come?—as some people slanderously charge us with saying. Their condemnation is just. (Romans 3:1-8)

Paul concluded that whether we believe it or not, Christ’s death on the cross paid the penalty for the sins of every person in the world and his resurrection demonstrated that God had provided the lamb himself as Abraham believed he would (Genesis 22:8). Paul used himself as an example to convey the point that a person’s unbelief justifies their condemnation because the truth is that everyone knows they are a sinner (Romans 3:9-20), but only those who are willing to admit the truth about themselves to God and others can and will be saved (Matthew 25:37-46; John 3:19-21; 1 John 1:9).