G-d asks Abraham to bring Isaac for a burnt offering

• G-d tested Abraham, and He said to him, "Abraham," and he said, "Here I am." And He said, "Please take your son, your only one, whom you love, yea, Isaac, and go away to the land of Moriah and bring him up there for a burnt offering on one of the mountains, of which I will tell you."
• Abraham arose early in the morning, took two young men with him and Isaac his son. On the third day, Abraham lifted up his eyes and saw the place from afar. He said to the young men, "Stay here with the donkey, and I and the lad will go yonder, and we will prostrate ourselves and return to you." Abraham placed the wood for the burnt offering, upon his son Isaac, and he took into his hand the fire and the knife, and they both went together.
• Isaac asked why they didn’t have a lamb for the burnt offering. Abraham replied, "G-d will provide for Himself the lamb for the burnt offering, my son." When they reached the place of which G-d had spoken, Abraham built an altar there, arranged the wood, bound Isaac and placed him on the altar upon the wood. And Abraham stretched forth his hand and took the knife, to slaughter his son.

G-d stops Abraham just as he is about to slaughter his son

• And an angel of G-d called to him from heaven and said, "Abraham! Abraham!" And he said, "Here I am." And he said, "Do not stretch forth your hand to the lad, nor do the slightest thing to him, for now I know that you are a God fearing man, and you did not withhold your son, your only one, from Me." And Abraham lifted up his eyes, and he saw, and lo! there was a ram, caught in a tree by its horns. And Abraham went and took the ram and offered it up as a burnt offering instead of his son.
• Abraham named that place, The Lord will see, as it is said to this day: On the mountain, the Lord will be seen.

G-d gives Abraham a great blessing

• An angel of the Lord called to Abraham a second time from heaven. And he said, "By Myself have I sworn, says the Lord, that because you have done this thing and you did not withhold your son, your only one, That I will surely bless you, and I will greatly multiply your seed as the stars of the heavens and as the sand that is on the seashore, and your descendants will inherit the cities of their enemies. And through your children shall be blessed all the nations of the world, because you hearkened to My voice." And Abraham returned to his young men, and they arose and went together to Beer-Sheba; and Abraham remained in Beer-Sheba.

• Here I am This is the reply of the pious. It is an expression of humility and an expression of readiness. — [from Tan. Vayera 22]
• the land of Moriah Jerusalem, and so in (II) Chronicles (3:1):“to build the House of the Lord in Jerusalem on Mount Moriah.” And our Sages explained that [it is called Moriah] because from there [religious] instruction (הוֹרָאָה) goes forth to Israel

• And an angel of G-d called to him from heaven G-d did not talk to Abraham directly , He communicated to him through angels.