good or be silent
Every Mukallaf should safeguard his tongue against all kinds of loose talk except when it is evident that talking will be a means of beneficence. When talking and being quiet are both equal as a prudent measure, then the Sunna is to abstain from speech. This is because even lawful speech may lead to unlawful or unpleasant matters. This is, unfortunately, a common practice. Abu-Hurairah reported that the Prophet ((صلي الله عليه وسلم) said:
"Whosoever believes in Allah and the Last Day should speak what is good or be silent."
This Hadith is clear and indisputable that a person should not talk unless what he wants to say is good and there is benefit from it. However, when he doubts whether there would be benefit or good, he should then not speak. Imam Shafi'ee said:
"If a person wishes to say something then he should think before he starts talking. If there is good, then he should speak, otherwise he should not."
Wa Alikum Assalaam Wa Rahmatullahi Wa Barakatuh!