Isaiah 41 tells us about that assurance that God told the people of Israel that they should have, that assurance that God would be with them and that they did not have to fear other nations.
1 Keep silence before me, O islands; and let the people renew their strength: let them come near; then let them speak: let us come near together to judgment.
2 Who raised up the righteous man from the east, called him to his foot, gave the nations before him, and made him rule over kings? he gave them as the dust to his sword, and as driven stubble to his bow.
3 He pursued them, and passed safely; even by the way that he had not gone with his feet.
4 Who hath wrought and done it, calling the generations from the beginning? I the Lord, the first, and with the last; I am he.
Isaiah 41:1-4 (KJV)
The prophet begins by speaking to the other nations, because when he refers to “coasts” it is as if he meant “islands” or “distant nations”. It is like calling all the surrounding nations to explain their deviation, idolatry, etc: Come and explain why you put your trust in other gods!
Then he continues talking about important events that have happened in humanity, meaning that these things have happened by the hand of God.
What is remarkable in these verses is that there is only one God to trust, who is the one who allows all things.
Israel must know that they had this God and that they should not fear other nations, and in the same way God has promised to be with us every day, until the end of time.
Finally, God says some incredible words to you in verse 10, and we should do them to ourselves:
Fear thou not; for I am with thee: be not dismayed; for I am thy God: I will strengthen thee; yea, I will help thee; yea, I will uphold thee with the right hand of my righteousness.