to preserve you as a remnant in the earth

"so that you and your families would not completely perish from the earth" or "to make sure your descendants would survive"

to keep you alive by a great deliverance

The abstract noun "deliverance" can be stated as "rescuing." AT: "to keep you alive by rescuing you in a mighty way" (See: rc://en/ta/man/translate/figs-abstractnouns)