(condensed from Ein Ayah, Shabbat 3:6)

Gemara: One who bathed in hot water but did not drink hot water is similar to one who heated an oven from the outside but not the inside.

Ein Ayah: This gemara teaches a nice moral insight related to the nature of protecting the body. It is more important to bathe in hot water for the purpose of protecting the body than for adorning himself externally. This makes one realize that external cleansing as a way to remove dirt from one’s exterior also requires that he clean his spirit, including purifying his heart from unseemly thoughts and his mind from problematic imagination.

One should always, including for external matters, turn toward the internal benefit he can receive from the matter. Then he will always choose for himself a beneficial approach to life. When focused on the internal, better things result, even in external matters, than if he intended only to improve the external. The appropriate metaphor for this is heating the oven. Heating it on the inside is more effective not only for heating the inside but even for heating the outside.

When a person loves and respects his spirit, despite the fact that he is too close to himself to be objective, this enables him to build the foundation of treating others properly. When one spreads out his efforts towards others, this behavior actually includes an element of crude love for himself, as he wants that all should love and respect him. This will not bring the desired result, as he will remain a slave to the masses without a healthy spirit in his own midst.

Regarding protecting one’s body, which relates both to the external and the internal, Hashem put into nature things that bring benefit in a way that trains people to put the emphasis on the internal. This fact should serve as the basis for concluding that the preference of the internal that he sees in nature is true also for the spiritual world. It is unwise to just bathe in hot water and not drink hot water or to heat an oven from the outside – [in the literal and metaphorical senses.]