hearken.

1 Samuel 8:7, 9
And the LORD said to Samuel, "Listen to the voice of the people in all that they say to you, for it is not you they have rejected, but they have rejected Me as their king. . . .

Isaiah 46:10
I distinguish the end from the beginning, and ancient times from what is still to come, saying: 'My purpose will be established, and I will accomplish all My good pleasure.'

in Isaac.

Genesis 17:19, 21
But God replied, "Your wife Sarah will indeed bear you a son, and you are to name him Isaac. I will establish My covenant with him as an everlasting covenant for his descendants after him. . . .

Romans 9:7, 8
Nor because they are Abraham's descendants are they all his children. On the contrary, "Through Isaac your offspring will be reckoned." . . .

Hebrews 11:18
even though God had said to him, "Through Isaac your offspring will be reckoned."