Gen 22:15-18

Then the angel of the LORD called to Abraham a second time from heaven,

and said, “By Myself I have sworn, declares the LORD, because you have done this thing and have not withheld your son, your only son,

indeed I will greatly bless you, and I will greatly multiply your seed as the stars of the heavens and as the sand which is on the seashore; and your seed shall possess the gate of their enemies.

“In your seed all the nations of the earth shall be blessed, because you have obeyed My voice.”

The Angel of the Lord is calling a second time from heaven.
He is reiterating the covenant promise that He spoke to Abraham earlier, Gen. 12, 15, etc.

God would greatly bless Abraham.
God would greatly multiply Abraham’s seed as the stars of the heavens and sand of the seashore.
Abraham’s seed would possess the gate of their enemies.
Through/in Abraham’s seed all the nations of the earth shall be blessed.

Why?
Because Abraham obeyed God’s voice.

A couple interesting things.
“Posses the gate of their enemies” ?
The Lord’s people will be victorious when all is said and done.
The Lord is their Victory.

Then, “by Myself I have sworn…”
When one swears/confirms it is done based upon a higher authority.
There is no higher authority than the Most High.
Therefore, He swore by Himself.
He Promised.
He declared that is would happen.
Blessings.
Multiplication.
Possession.

Rejoice!