41:10 - fear not, for I am with you; be not dismayed, for I am your God; I will strengthen you, I will help you, I will uphold you with my righteous right hand.and
43:1-3 - “Fear not, for I have redeemed you; I have called you by name, you are mine. When you pass through the waters, I will be with you; and through the rivers, they shall not overwhelm you; when you walk through fire you shall not be burned, and the flame shall not consume you. For I am the Lord your God, the Holy One of Israel, your Savior.Notice how the first promise comes with information on exactly why we shouldn't fear: God will strengthen us, help us, and uphold us. One of those things would be nice to know, but God piles on 3 things to reinforce His commitment to us. The next verse He piles on descriptions of His love toward us: He redeemed us, called us by name, and made us His.
God extravagantly reassures us with His promises. What a good God!