Matthew 6:16
"In addition, when you fast [i.e., go without food and/or drink for religious reasons], do not be like the hypocrites with long faces, for they go around with gloomy expressions on their faces in order to advertise that they are fasting. It is true when I say to you, these people have [already] received their reward.
Romans 12:15
Be happy with those who are joyful. Cry with those who are sad.
Hebrews 13:3
Remember [to pray for and help] those who are in prison, as though you [yourselves] were in prison with them. [Remember] those who are being mistreated, realizing that you [yourselves] also share [with them] a physical body [i.e., you are subject to the same kind of trials].