I have heard the groaning of the children of Israel — He means their groaning on occasion of the late hardships put upon them. God takes notice of the increase of his people's calamities, and observes how their enemies grow upon them.
Related Commentaries of Exodus 6:5
Exodus 6:5
5 And I have also heard the groaning of the children of Israel, whom the Egyptians keep in bondage; and I have remembered my covenant.