Article 636... to have equanimity towards grief and joy.. is to be emotionally steady

When a plane flies across the sky,
it leaves no mark on it, no streak that lasts,
no furrow or pothole that interferes with further traffic.

So too, witness all the feelings and emotions
as they cross your mind, but, do not allow them
to make an impression on you.

This can be done by inquiry, by quiet reasoning
within oneself, more than by listening to lectures or study of books.

from a divine source