General Information:

Isaiah continues speaking.

our many transgressions

Here "our" refers to Isaiah and the people of Israel. (See: rc://en/ta/man/translate/figs-inclusive)

Here "you" refers to Yahweh. (See: rc://en/ta/man/translate/figs-you)

Isaiah describes the sins as a person who goes before God to declare that the people are guilty. (See: rc://en/ta/man/translate/figs-personification)

"With us" represents being aware of them. AT: "for we are aware of our transgressions" (See: rc://en/ta/man/translate/figs-metaphor)