Marcus Tullius Cicero Quotes about Grieving

Marcus Tullius Cicero, Maurice MACKAY (1855). “Select Orations of Marcus T. Cicero: together with the Treatises on Old Age and Friendship. Literally translated by the Rev. Dr. M'Kay ... Second edition”, p.138
This is a proof of a well-trained mind, to rejoice in what is good and to grieve at the opposite.
"Hoyt's New Cyclopedia Of Practical Quotations" by Jehiel Keeler Hoyt, De Amicitia, XIII, p. 326-29, 1922.