Hebrews 13:2-3

Hebrews 13:2-3. Be not forgetful to entertain strangers: for thereby some have entertained angels unawares. Remember them that are in bonds, as bound with them; and them which suffer adversity, as being yourselves also in the body.

And being likely therefore to take your own turn of suffering, and to need the sympathy of your fellow-Christians. Show sympathy to others while they need it, and they will gratefully remember you when you are in bonds or in adversity.