Musar su Deuteronomio 4:15

Perhaps you will say: behold we see that the sages everywhere obligated a man to guard himself well and not put himself in danger even if he is a righteous person with many merits. For instance: "everything is in the hands of heaven except colds and heatstrokes" (Ketubot 30a) and the Torah says "you shall guard yourselves very carefully" (Devarim 4:15). Hence one should not decide to "trust in G-d" in all situations, and in the Talmud Yerushalmi (Berachot 3, see also Chulin 142a) they said: "even when performing a Mitzva!".

But he is still not master over himself to keep his heart from being pulled by natural lusts so that they do not sway him to rationalize that certain things are permitted regarding the things whose evil is not so well known.

For even though he strives to conquer his evil inclination and to subdue his lusts, he will not change his nature because of this. He will not be able to remove bodily lust from his heart. He will at most be able to subdue it and be governed by wisdom instead of it. But nevertheless the darkness of the physical will inevitably do its work to entice and seduce him.