Taskmasters - Oppressors. A different word from that in Exodus 1:11.
I know - The expression implies personal feeling, tenderness, and compassion (compare Exodus 2:25 margin).
Related Commentaries of Exodus 3:7
Exodus 3:7
7 And the LORD said, I have surely seen the affliction of my people which are in Egypt, and have heard their cry by reason of their taskmasters; for I know their sorrows;