“I will surely be with you,” God said, “and this will be the sign to you that I have sent you: When you have brought the people out of Egypt, all of you will worship God on this mountain.”
Jewish Publication Society of America Version (JPS1917) - Exodus 3:12 >And He said: 'Certainly I will be with thee; and this shall be the token unto thee, that I have sent thee: when thou hast brought forth the people out of Egypt, ye shall serve God upon this mountain.'