سنن أبي داود

Narrated Buhaisah: On the authority of her father: My father asked the Prophet (ﷺ) for permission (to kiss his body). (When he was given permission), lifting his shirt he approached his body, and began to kiss and stick to him. He then asked: Prophet of Allah, what is the thing withholding of which is not lawful ? He replied: Water. He asked: Prophet of Allah, what is the thing withholding of which is not lawful ? He replied: Salt. He again asked: Prophet of Allah, what is the thing withholding of which is not lawful ? He said: That you do a good work is better for you.