Yahweh recognizes Israel’s anxiety. Even though they are not experiencing an oppressor’s fury, they are still captive. Yahweh understands the captive’s desire to be free and master of his own destiny rather than fearing he will die in the pit or not receive his ration of bread. Still, Yahweh reminds them of his power. Even in their captivity, God is there.
Comparison: Verse 15 does not follow the Isaiah text: “but I am the Lord thy God that divided the sea, whose waves roared.” The omitted phrase “that divided the sea” does not exist in the original manuscript. Skousen lists several locations where a phrase from the original Isaiah passage is not represented in the Book of Mormon text. There is no available reason for the absence of the phrase here, or in most of the other cases. I suggest that it is simply an error.