Jesus uses a question to teach the disciples. AT: "You know that five sparrows are sold for only two small coins" (See: [[rc://en/ta/man/translate/figs-rquestion]])
This could be stated in active form and in positive form. AT: "God never forgets any of them" or "God indeed remembers every sparrow" (See: [[rc://en/ta/man/translate/figs-activepassive]] and [[rc://en/ta/man/translate/figs-litotes]])
The reason for the fear is not stated. Possible meanings are 1) "Do not be afraid of what will happen to you" or 2) "So do not be afraid of people who could hurt you."