The emphasis here is on before our eyes.
The Israelites witnessed how severely the Lord struck the Egyptians. Ten terrible plagues (Exodus 7:1–11:10) ravaged the people, animals, and nature in Egypt. These shocking events were to stay with them. They were never to forget how deeply the Lord struck the Egyptians, from their highest to their lowest. Thus, the Lord punished that nation and simultaneously chastised all the Egyptian gods (Exodus 12:12). Witnessing God's great and grievous wonders is an immediate encouragement to realize for themselves how powerful the Lord is, and to remember, the Lord alone is God; there is no other besides Him
(Deuteronomy 4:35).
22 And the LORD showed signs and wonders, great and grievous, against Egypt and against Pharaoh and all his household, before our eyes.