Exodus 9:14

9:14 For this time I will send all my plagues on your very self and on your servants and your people, so that you may know that there is no one like me in all the earth.

Exodus 19:9

19:9 The Lord said to Moses, “I am going to come to you in a dense cloud, so that the people may hear when I speak with you and so that they will always believe in you.” And Moses told the words of the people to the Lord.