(1) Some time afterward, God put Abraham to the test, saying to him, “Abraham.” He answered, “Here I am.” (2) “Take your son, your favored one, Isaac, whom you love, and go to the land of Moriah, and offer him there as a burnt offering on one of the heights that I will point out to you.” (3) So early next morning, Abraham saddled his ass and took with him two of his servants and his son Isaac. He split the wood for the burnt offering, and he set out for the place of which God had told him. (4) On the third day Abraham looked up and saw the place from afar. (5) Then Abraham said to his servants, “You stay here with the ass. The boy and I will go up there; we will worship and we will return to you.” (6) Abraham took the wood for the burnt offering and put it on his son Isaac. He himself took the firestone and the knife; and the two walked off together. (7) Then Isaac said to his father Abraham, “Father!” And he answered, “Yes, my son.” And he said, “Here are the firestone and the wood; but where is the sheep for the burnt offering?” (8) And Abraham said, “It is God who will see to the sheep for this burnt offering, my son.” And the two of them walked on together. (9) They arrived at the place of which God had told him. Abraham built an altar there; he laid out the wood; he bound his son Isaac; he laid him on the altar, on top of the wood. (10) And Abraham picked up the knife to slay his son. (11) Then a messenger of יהוה called to him from heaven: “Abraham! Abraham!” And he answered, “Here I am.” (12) “Do not raise your hand against the boy, or do anything to him. For now I know that you fear God, since you have not withheld your son, your favored one, from Me.” (13) When Abraham looked up, his eye fell upon a*a Reading ’eḥad with many Heb. mss. and ancient versions; text ’aḥar “after.” ram, caught in the thicket by its horns. So Abraham went and took the ram and offered it up as a burnt offering in place of his son. (14) And Abraham named that site Adonai-yireh, whence the present saying, “On the mount of יהוה there is vision (15) The messenger of יהוה called to Abraham a second time from heaven, (16) and said, “By Myself I swear, יהוה declares: Because you have done this and have not withheld your son, your favored one, (17) I will bestow My blessing upon you and make your descendants as numerous as the stars of heaven and the sands on the seashore; and your descendants shall seize the gates of their foes. (18) All the nations of the earth shall bless themselves by your descendants, because you have obeyed My command.”

AND GOD TRIED ABRAHAM.
...Know that God trieth the righteous (Psalms 11:5), for knowing that the righteous will do God's will, God desires to make him even more righteous, and so God commands him to undertake a test, but God does not try the wicked, who would not obey. Thus all trials in the Torah are for the good of the one who is being tried.

Here, also, "After these events," that Abraham made a pact – obligating himself, his children and his grandchildren – with Abimelech and gave him the seven ewes of the flock; and God became angry about this, since the land of the Philistines is included in the Israelite borders, within which God commanded, "You shall not let a soul stay alive", and in Joshua lots were cast over the cities of the five Philistine lords; accordingly, God tested (nissah) Abraham," i.e. He provoked him and caused him pain.

It is very difficult to explain the matter of G’d’ “testing” someone, seeing that G’d knows in advance what the result of such a test is going to be. What then is the point of such a test? If the point was to demonstrate to the world at large that Abraham successfully passed such a test, how could this be accomplished in a setting where only Abraham and Isaac were present? ...

The truth is that the purpose of the trial was to demonstrate to the world Abraham's love for God. It was not meant to demonstrate anything to the generation during which Abraham lived, but to prove this to subsequent generations of people who believed in the Torah which was handed down to us by Moses at the command of God.

In reality all questions are removed by Scripture’s first stating that God did prove Abraham. The reason God tested Abraham was in order to reward him.

את בנך THY SON — Abraham said to God, “I have two sons”. “He answered him, “Thine only son”. Abraham said, “This one is the only son of his mother and the other is the only son of his mother”. God then said, “the one who you love”. Abraham replied, “I love both of them”. Then God said “even Isaac”. Why did God not disclose this to him at the very first? So as not to confuse him suddenly lest his mind become distracted and bewildered and in his confused state he would involuntarily consent, when there would have been no merit in his sacrifice, and so that he might more highly value God’s command and that God might reward him for the increasing sacrifice demanded by obedience to each and every expression used here (Genesis Rabbah 55:7).

על אחד ההרים, even now God did not tell Abraham precisely on which mountain he was to offer up Isaac as a burnt offering. Instead, God only said: "that I will tell you", just as when he said to him "to the land that I will show you" (Genesis 12:1) This [vagueness] was to emphasize the readers our patriarch Abraham's love for God. He did not ask or try, he did not ask why, he did not ask why he must offer him at a place three days away or why not offer him now in this place?

There were two reasons [why he told Abraham in this way] to emphasize Abraham's love, that if God said to him "offer him now in your place" it would have been sudden and he would have been shocked and not able to understand and perform the commandment suddenly as it was commanded to him. But by extending the time of the offering over three days gave him time to comprehend the thing and if he still did all that God asked of him quickly, this is a great thing.

וילכו שניהם יחדיו THEY WENT BOTH OF THEM TOGETHER — with equal heart (Genesis Rabbah 56:4).

AND HE CLEAVED THE WOOD FOR THE BURNT-OFFERING. This illustrates Abraham’s zeal in performing a commandment for he thought that perhaps there would be no wood in that place, and so he carried it for three days. It may be that Abraham disqualified for use as an offering any wood in which a worm is found, as is the law of the Torah, and so he took from his house sound wood for the burnt-offering. Hence it says, And he cleaved the wood for the burnt-offering.

FOR NOW I KNOW THAT THOU ART A GOD FEARING MAN. At the beginning Abraham’s fear of God was latent; it had not become actualized through such a great deed. But now it was known in actuality, and his merit was perfect, and his reward would be complete from the Eternal, the God of Israel.

Some ask, how could Abraham say, and (we will) come back to you (v. 5)? Others answer them by saying that Abraham intended to return with Isaac’s bones, and he disguised his intentions so that his young men would wait for him till he returned and Isaac would not know what was about to happen and flee.

Our sages, of blessed memory, say that Isaac was thirty-seven years old at the time of his binding. If this be a tradition, we will accept it. However, from a strictly logical point of view it is unacceptable. If Isaac was an adult at this time, then his piety should have been revealed in Scripture and his reward should be double that of his father for willingly having submitted himself to be sacrificed. Yet Scripture says nothing concerning Isaac’s great self-sacrifice.

Others say that Isaac was five years old at the time of his binding. This, too, is unacceptable, since Isaac carried the wood for the sacrificial pyre. It thus appears logical to assume that Isaac was close to thirteen years old and that Abraham overpowered him and bound him against his will. Proof of this can be seen from the fact that Abraham hid his intention from Isaac and told him, God will provide Himself the lamb for a burnt-offering, my son (v. 8). Abraham knew that if he said, “You are to be the burnt-offering,” Isaac would quite possibly have fled.