God knows about their unfaithfulness (Isa 65:6-65:7)

“See!

It is written before me!

‘I will not keep silent.

But I will repay.

I will indeed repay into their laps

For their iniquities

With their ancestor’s iniquities together.’

Says Yahweh.

‘Because they offered incense

On the mountains,

They reviled me on the hills.

I will measure into their laps

Full payment for their actions.’”

Their actions have not gone unnoticed. Yahweh saw what was happening since it was written before him. He was not going to be silent. He wanted them to pay back for what they did. They would not only have to pay for their own sins and iniquities, but also repay for the sins of their ancestors. They have offered incense on the mountains and reviled Yahweh in the hills. He was going to measure out for them the full payment for their actions.