Genesis 22:20

And it came to pass after these things, that it was told Abraham, saying, Behold, Milcah, she hath also born children unto thy brother Nahor;


Geneva Bible - And after these things one told Abraham, saying, Behold Milcah, she hath also born children unto thy brother Nahor;

Genesis 22:19

So Abraham returned unto his young men, and they rose up and went together to Beer-sheba; and Abraham dwelt at Beer-sheba.


Geneva  Bible - Then turned Abraham again unto his servants, and they rose up and went together to Beer-sheba; and Abraham dwelt at Beer-sheba.

Genesis 22:18

And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.


Geneva Bible - (*) And in thy seed shall all the nations of the earth be blessed, because thou
hast obeyed my voice.
(*) Genesis 12:3; Genesis 18:18; Acts 3:25; Galatians 3:8 .

Note:  In blessing all the nations of the earth because of Abraham, we have a two-pronged prophecy:  One, that the seed of Abraham (via Isaac, Jacob who is Israel), all nation's are blessed because of God's peculiar relationship with Israel, and two, because out of Israel via the tribe of Judah will come forth God's Son, Jesus Christ, by whom all the nation's of the earth and it's peoples are reconciled to God IF they believe on Him.

Genesis 22:17

That in blessing I will bless thee, and in multiplying I will multiply thy seed as the stars of the heaven, and as the sand which [is] upon the sea shore; and thy seed shall possess the gate of his enemies;


Geneva Bible - Therefore will I surely bless thee, and will greatly multiply thy seed, as the stars of the heaven, and as the sand which is upon the seashore, and thy seed shall possess the (*) gate of his enemies.
(*) Or, holds.

Genesis 22:16

And said, By myself have I sworn, saith the LORD, for because thou hast done this thing, and hast not withheld thy son, thine only [son:]


Geneva Bible - And said, (*) By (h) myself have I sworn (saith the LORD) because thou hast done this thing, and hast not spared thine only son,
(*) Psalm 105:9; Luke 1:73; Hebrews 6:13 .
(h) Signifying, that there is no greater than he.

Genesis 22:15

And the angel of the LORD called unto Abraham out of heaven the second time,


Geneva Bible - And the Angel of the LORD cried unto Abraham from heaven the second
time,

Genesis 22:14

And Abraham called the name of that place Jehovah-jireh [the Lord will provide or see]: as it is said [to] this day, In the mount of the LORD it shall be seen [provided].


Geneva Bible - And Abraham called the name of that place, (*) Jehovah-jireh, as it is said this day, In the mount will the LORD (g) be seen.
(*) Or, the Lord will see or provide.
(g) The name is changed, to shew that God doeth both see and provide secretly for his, and also
evidently is seen and felt in the time convenient.

Genesis 22:13

And Abraham lifted up his eyes, and looked, and behold behind [him] a ram caught in a thicket by his horns: and Abraham went and took the ram, and offered him up for a burnt offering in the stead of his
son.

Geneva Bible - And Abraham lifting up his eyes, looked, and behold, there was a ram behind him caught by the horns in a bush; then Abraham went and took the ram, and offered him up for a burnt offering in the stead of his son.

My commentary:  Just as Abraham was willing to offer up his only true son, the promised seed for salvation of the world (Jesus himself would be born through the descendents of Isaac), God offered his only son once, to take on all the sins of the entire world.  Abraham was given a Ram as a substitute, which is what the Jew's would do until the day of Jesus Christ.  When he was offered as the final substitute offering on the cross at Golgatha, the veil was torn (split) in two, showing the holy of holies was no longer needed (No more sacrifice required to God for a sin offering of the entire peoples).  What God kept Abraham from doing, in his love of Abraham, he was willing to do for all of us, to this very day, in offering his Son as the last perfect, unblemished Lamb of God.

Genesis 22:12

And he said, Lay not thine hand upon the lad, neither do thou any thing unto him: for now I know that thou fearest God, seeing thou hast not withheld thy son, thine only [son] from me.


Geneva Bible - Then he said, Lay not thine hand upon the child, neither do anything unto him; for now I (f) know that thou fearest God, seeing for my sake (*) thou hast not spared thine (♣) only son.
(f) That is, by thy true obedience thou hast declared thy lively faith.
(*) Or, and hast not withholden thine only son from me.
(♣) Hebrew: thy son, the only son.

My commentary:  God prevents Abraham from commiting the sacrifice, as God abhors human sacrifice of any kind (This is what would cause the destruction of the peoples of Canaan when the Israelites are entering).  God was TESTING Abraham, to see if he would believe and trust God (Faith), that even though he promised him his seed would be the heir (Isaac) of the promise by God, that he would believe and trust him and sacrifice his son.  Once Abraham passed the test, God stopped him.

As to whether people today believe God was merciless or cruel in doing this, please consider that God Himself, would offer up his only begotten Son, Jesus Christ, who entered this world through the seed of Isaac, as the last blood sacrifice to rid the world of sin forever.  That Son would be the perfect, unblemished lamb of God, who would take on all the sin's of the world and all the agony it entailed, and be tortured and hung on a tree, ending once and for all the requirement of a blood sacrifice for the reproachment of sin.

Genesis 22:11

And the angel of the LORD called unto him out of heaven, and said, Abraham, Abraham: and he said,
Here [am] I.

(Geneva Bible) - But the Angel of the LORD called unto him from heaven, saying, Abraham, Abraham. And he answered, Here am I.