Musar zu Mischlej 3:6

I am surprised that when it comes to smallpox outbreaks, which spreads from child to child, why do people not take their children out of the city? In the future, the fathers will be responsible for the deaths of their children who are nursing, and have committed no sin, and those who are weaned and have committed no sins, and died from the sickness whose fathers did not take them away [from the city]. Every man who fears god should fear every eventuality. These things that are included in protecting the body are included in the warnings of (Devarim 4:9) 'take utmost care and watch yourselves scrupulously' and this is also the way of the world to take care of one's body since it is the container that the soul is wrapped up in so it will be a throne for the soul.

He who wishes to escape from the fowler's net of all these loves will need great wisdom and much courage, lest he be caught in their pit for all of these various loves surround the heart of a person, and if he succeeds in thrusting away one or two of these loves from within him, then will the remaining loves still thrust him from the light to the darkness. Therefore it is necessary to teach you that you should be careful and alert as to how to deal with all of these loves and always be mindful in combatting them of the ways of the Lord, Blessed is He, according to the tenor of what is said: "In all your paths know Him (Prov. 3:6).

He who walks in the path described above serves the Lord, may He Be Blessed, always, even when he is engaged in doing business, even when he lives with his wife, for his intention is to fulfill his bodily needs so that he can serve God, Blessed be He. And even when he sleeps, if he sleeps, so that his mind will be refreshed and his body rested, so that he does not become ill and therefore not be able to serve the Lord, Blessed is He, because of his illness — that sleep with this intent is considered service to God, Blessed be He. And on this subject our Sages commanded and said: "Let all your deeds be for the sake of Heaven (God)" (Aboth 2:17). And this is what Solomon said in his wisdom: "In all thy ways, know Him and He will direct your paths" (Prov. 3:6).