The Axis of Virtue

Abu Dawud mentions that the hadith, "Part of one's being a good Muslim is leaving alone that which does not concern him" is one of four hadiths around which rulings revolve. The details of the four hadiths can be found in the hyperlinked biography of the imam but have been summarized in two couplets:

عمدة الدين عندنا كلمات________من قول خير البرية

اترك الشبهات وازهد ودع ما_____ليس يعنيك و اعملن بنية

meaning,

The basis of the religion, according to us, are words
From the speech of the Best of Creation:
Shun doubtful matters, be abstinent, leave that
Which does not concern you and act with intention.