Exodus 6:1
Then the LORD said unto Moses, Now shalt thou see what I will do to Pharaoh: for with a strong hand shall he let them go, and with a strong hand shall he drive them out of his land. Then the LORD said unto Moses, Now shalt thou see what I will do to Pharaoh: for with a strong hand shall he let them go, and with a strong hand shall he drive them out of his land.
Then the Lord told Moses that now he would see for himself what God would do to Pharaoh to bring Israel out of Egypt. The strong hand is God's own mighty power compelling the outcome, not Pharaoh's willingness nor Moses' ability, so that Pharaoh would not merely let Israel go but would forcibly drive them out of his land. The promise answered Moses' distress after Pharaoh increased the people's burdens, when worsening oppression and suffering made deliverance seem farther off.
The promised deliverance fulfilled God's covenant with Israel's forefathers and ancestors. That deliverance was delayed because the people lacked faith and readiness to endure hardship, and many had become attached to Egypt. God allowed the worsening oppression to expose Pharaoh's tyranny and to display His own power, justice, and love to both Egyptians and Israelites, so the people would become eager to leave Egypt and choose to serve Him. The verse thus exemplifies the opposition and hardship God's people face when working to warn others and call them to change.