For why? He remembered his holy promise which he had made to Abraham his servant.

And their complaint came up unto God from the labour. And God remembered his covenant with Abraham, Isaac and Jacob.

Then the LORD appeared unto Abram and said, "Unto thy seed will I give this land." And he built an altar there unto the LORD which appeared to him.

And the LORD said unto Abram, after that Lot was departed from him, "Lift up thine eyes and look from the place where thou art, northward, southward, eastward and westward,

And he said unto Abram, "Know this of a surety, that thy seed shall be a stranger in a land that pertaineth not unto them. And they shall make bondmen of them and entreat them evil, four hundred years.

Remember Abraham, Isaac and Israel thy servants, to whom thou sworest by thine own self and saidest unto them, 'I will multiply your seed as the stars of heaven, and all this land which I have said, I will give unto your seed: and they shall inherit it forever.'"

It is not for thy righteousness' sake and right heart that thou goest to possess their land: But partly for the wickedness of these nations, the LORD thy God doth cast them out before thee, and partly to perform that which the LORD thy God sware unto thy fathers, Abraham, Isaac and Jacob.

Remember thy servants Abraham, Isaac and Jacob and look not unto the stubbornness of this people nor unto their wickedness and sin:

He is always mindful of his covenant and promise, that he made to a thousand generations,

Thou shalt keep thy trust with Jacob, and thy mercy for Abraham, like as thou hast sworn unto our fathers long ago.

He remembereth mercy: and helpeth his servant Israel.

To fulfill the mercy promised to our fathers; And to remember his holy covenant;

Treasury of Scripture Knowledge

Summary

For he remembered his holy promise, and Abraham his servant.

Bible References

For he

He is always mindful of his covenant and promise, that he made to a thousand generations,
Then the LORD appeared unto Abram and said, "Unto thy seed will I give this land." And he built an altar there unto the LORD which appeared to him.
And the LORD said unto Abram, after that Lot was departed from him, "Lift up thine eyes and look from the place where thou art, northward, southward, eastward and westward,
But the nation whom they shall serve, will I judge. And afterward shall they come out with great substance.
And their complaint came up unto God from the labour. And God remembered his covenant with Abraham, Isaac and Jacob.
He remembereth mercy: and helpeth his servant Israel.

Abraham

Remember Abraham, Isaac and Israel thy servants, to whom thou sworest by thine own self and saidest unto them, 'I will multiply your seed as the stars of heaven, and all this land which I have said, I will give unto your seed: and they shall inherit it forever.'"
It is not for thy righteousness' sake and right heart that thou goest to possess their land: But partly for the wickedness of these nations, the LORD thy God doth cast them out before thee, and partly to perform that which the LORD thy God sware unto thy fathers, Abraham, Isaac and Jacob.
Thou shalt keep thy trust with Jacob, and thy mercy for Abraham, like as thou hast sworn unto our fathers long ago.
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