en_obs-tn/content/25/04.md

throw yourself down

That is, "jump off this building to the ground."

it is written

That is, "a prophet of God wrote long ago."

so your foot does not hit a stone

This means, "so that you will not be hurt at all; not even your foot will be injured on a stone." It could also be translated as, "so that even your foot will not strike against a stone; you will not be injured at all."