The great lesson is, that unity is behind all. Call it God, Love, Spirit. Allah, Jehovah - it is the same unity that animates all life from the lowest animal to the noblest man.
Learn to feel yourself in other bodies, to know that we are all one. Throw all other nonsense to the winds. Spit out your actions, good or bad, and never think of them again. What is done is done. Throw off superstition. Have no weakness even in the face of death. Be free.
My son, there is no rest for me. That which Sri Ramakrishna called "Kali" took possession of my body and soul three or four days before his passing away. That makes me work and work and never lets me keep still or look to my personal comfort.
There are hundreds of thousands of microbes surrounding us, but they cannot harm us unless we become weak, until the body is ready and predisposed to receive them.
In this external world, which is full of finite things, it is impossible to see and find the Infinite. The Infinite must be sought in that alone which is infinite, and the only thing infinite about us is that which is within us, our own soul. Neither the body, nor the mind, nor even our thoughts, nor the world we see around us, is infinite.