Romans 9:7

Neither are they all children straightway because they are the seed of Abraham: But in Isaac shall thy seed be called,

Genesis 21:12

Then the LORD said unto Abraham, "Let it not be grievous unto thee, because of the lad and of thy bondmaid: But in all that Sara hath said unto thee, hear her voice, for in Isaac shall thy seed be called.

Hebrews 11:18

Of whom it was said, "In Isaac shall thy seed be called."

Luke 3:8

Bring forth due fruits of repentance; And begin not to say in yourselves, we have Abraham to our father. For I say unto you: God is able of these stones to raise up children unto Abraham.

Luke 16:24-25

And he cried and said, 'Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, and cool my tongue, for I am tormented in this flame.'

Luke 16:30

And he said, 'Nay, father Abraham, but if one came unto them from the dead they would repent.'

John 8:33

They answered him, "We be Abraham's seed, and were never bond to any man: why sayest thou then, 'Ye shall be made free?'"

John 8:37-39

I know that ye are Abraham's seed: but ye seek means to kill me because my sayings have no place in you.

Galatians 4:23

Yea, and he which was of the bondwoman, was born after the flesh: but he which was of the freewoman, was born by promise.

Philippians 3:3

For we are circumcision which worship God in the spirit, and rejoice in Christ Jesus, and have no confidence in the flesh:

Treasury of Scripture Knowledge

Summary

Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.

General references

Bible References

Because

Luke 3:8
Bring forth due fruits of repentance; And begin not to say in yourselves, we have Abraham to our father. For I say unto you: God is able of these stones to raise up children unto Abraham.
Luke 16:24
And he cried and said, 'Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, and cool my tongue, for I am tormented in this flame.'
John 8:37
I know that ye are Abraham's seed: but ye seek means to kill me because my sayings have no place in you.
Philippians 3:3
For we are circumcision which worship God in the spirit, and rejoice in Christ Jesus, and have no confidence in the flesh:

In isaac

Genesis 21:12
Then the LORD said unto Abraham, "Let it not be grievous unto thee, because of the lad and of thy bondmaid: But in all that Sara hath said unto thee, hear her voice, for in Isaac shall thy seed be called.
Hebrews 11:18
Of whom it was said, "In Isaac shall thy seed be called."

General references

Genesis 21:3
And Abraham called his son's name that was born unto him, which Sara bare him, Isaac:
Genesis 25:5
But Abraham gave all that he had unto Isaac.