Conceal your good deeds, just as you conceal your bad deeds.
ar-Rabee’ ibn Khuthaym only ever prayed a voluntary prayer in his local masjid once.
I accompanied Muhammad ibn Aslam for more than 20 years, and never once saw him praying a voluntary prayer except on the day of Jumu’ah; [I understood why, when] I once heard him saying: ‘If I was able to pray a voluntary prayer such that my two angels could not see me, I would have done so – out of fear of showing off’.
If any member of the household entered upon ‘Abdur-Rahmaan ibn Abee Laylaa while he was [standing the night] praying, he would immediately jump into bed [out of humility, and remaining sincere in his worship to Allaah, and being far removed from showing off].
Whoever asks a question whilst he knows [the answer], then that is [considered to be] bordering on showing off.