Exodus 2:23 And it came to pass in process of time, that the king of Egypt died: and the children of Israel sighed by reason of the bondage, and they cried, and their cry came unto God by reason of the bondage.
Moses, having been saved from the slaughter of baby boys, grew up and visited his people. In indignation and rage he killed an Egyptian slave master. The thing became known, and Moses had to flee for Pharaoh had sought to kill him. When that Pharaoh died, God’s people were still under oppressive bondage.
Because of the cruel bondage of slavery, the people sighed and cried. God heard their cry and took it as prayer. Romans 8:26-27: ”The Spirit himself intercedes for us with groanings too deep for words.” Where was God? It’s been 400+ years since He promised. Now God would act.
The whole OT Exodus Event prefigures the NT Deliverance through the death and resurrection of Jesus Christ. Here the story prefigures our own response to the cruel slavery to Sin and Death that we experience in this life. We sigh and groan and cry out to God by reason of the bondage to Sin and Death. Although we suffer from our own sins and the sins of others, we still need a revelation from God regarding the depth of depravity and the strong hold of sin. When we see it, by the preaching of the Law, we sigh and groan and cry. Our groans reach the ear of God as prayer. He responds and delivers.