Reward of safeguarding one’s tongue
Thawāb al-Aʿmāl wa ʿiqāb al-Aʿmāl|Volume 1|Book 2|Chapter 408
أَبِی ره عَنْ سَعْدِ بْنِ عَبْدِ اللَّهِ عَنْ مُعَاوِیَهَ بْنِ حُکَیْمٍ عَنْ مُعَمَّرِ بْنِ خَلَّادٍ عَنْ أَبِی الْحَسَنِ الرِّضَا ع عَنْ أَبِیهِ قَالَ قَالَ أَبُو عَبْدِ اللَّهِ ع نَجَاهُ الْمُؤْمِنِ فِی حِفْظِ لِسَانِهِ. وَ قَالَ أَمِیرُ الْمُؤْمِنِینَ ع مَنْ حَفِظَ لِسَانَهُ سَتَرَ اللَّهُ عَوْرَتَهُ.
From my father رضي الله عنه through Saʿd ibn ʿAbdullāh, from Muʿāwiyah ibn Ḥukaim, from Muʿammar ibn Khallād, from Abū al-Ḥasan al-Riḍā عليه السلام, from his father, who said that Abū ʿAbdullāh عليه السلام stated: "The salvation of a believer lies in safeguarding his tongue." And Amīr al-Muʾminīn عليه السلام said: "Whoever safeguards his tongue, Allah will conceal his faults."