Here "lifted up my hand" is a symbolic action that shows he will truly do what he has sworn to do. Alternate translation: "I myself also solemnly swore" (See: [[rc://en/ta/man/translate/translate-symaction]])
These two phrases mean basically the same thing. See how you translated this in [Ezekiel 12:15](../12/15.md). Alternate translation: "cause them to separate from each other and live in different nations" (See: [[rc://en/ta/man/translate/figs-parallelism]])