God was talking to Israel in Exodus 14:14.
Jesus was talking to his 72 disciples in Luke 10. He wasn't talking to believers today.
(Luke 10:1 NIV) After this the Lord appointed seventy-two others and sent them two by two ahead of him to every town and place where he was about to go.
(Luke 10:17-20 NIV) The seventy-two returned with joy and said, "Lord, even the demons submit to us in your name." {18} He replied, "I saw Satan fall like lightning from heaven. {19} I have given you authority to trample on snakes and scorpions and to overcome all the power of the enemy; nothing will harm you. {20} However, do not rejoice that the spirits submit to you, but rejoice that your names are written in heaven."
We don't have to remind God of his promises. God is not a man who can forget, change his mind, or needs to be reminded. Most of what people consider the promises of God are things God said to certain people in certain situations that don't apply to believers today.
Yes, nothing is impossible for God. Nothing is too big or too small. But we shouldn't expect miracles from God on a regular basis.