سورة الأحزاب

Imam Sadiq (peace be upon him): Yunus narrated: Imam Sadiq (peace be upon him) said to Abbad ibn Kathir al-Basri al-Sufi: "Woe to you, O Abbad! Has the fact that you have kept your stomach and private parts chaste made you conceited? Allah the Mighty and Majestic says in His Book: يَا أَیُّهَا الَّذِینَ آمَنُوا اتَّقُوا اللهَ وَ قُولُوا قَوْلًا سَدِیدًا* یُصْلِحْ لَکُمْ أَعْمَالَکُمْ [O you who believe! be careful of (your duty to) Allah and speak the right word, He will put your deeds into a right state for you]. Know that Allah will not accept any deed from you unless you speak qawl sadid (the word of truth)."

Imam Sadiq (peace be upon him): Allah the Exalted made faith obligatory upon the limbs of the children of Adam (peace be upon him) and apportioned it among the limbs ... and He made it obligatory upon the tongue to affirm that which the heart has bound itself to. So He said: قُولُوا آمَنَّا [Say: We believe in Allah]. (Baqarah/136). And He said: وَ قُولُوا لِلنَّاسِ حُسْناً [And speak good to people]. (Baqarah/83). And He said: وَ قُولُوا قَوْلًا سَدِیداً [And speak the right word]. And He said: وَ قُلِ الْحَقُّ مِنْ رَبِّکُمْ [Say: The truth is from your Lord]. (Kahf/29). [And the like of what Allah has commanded to be uttered.] This is what Allah has made obligatory upon the tongue, and this is its deed.

Imam Rida (peace be upon him): Do not abandon righteous deeds and striving in worship, relying on love for the family of Muhammad (peace be upon him and his family); and do not abandon love for the family of Muhammad (peace be upon him and his family) and submission to their command, relying on worship — for neither of the two is accepted without the other. Know that the head of obedience to Allah is submission to what we understand and what we do not understand, just as the head of sins is rejecting them. Allah the Mighty and Majestic tests people through obedience in what they understand and what they do not understand, so that the proof may be established and doubt removed. وَ اتَّقُوا اللهَ وَ قُولُوا قَوْلًا سَدِیداً یُصْلِحْ لَکُمْ أَعْمالَکُمْ [Be careful of (your duty to) Allah and speak the right word, He will put your deeds into a right state for you]. And He will admit you into gardens of Paradise beneath whose trees rivers flow, and into pure dwellings in the gardens of eternity. (Saff/12). Let not the good of this world escape you, for the Hereafter cannot be attained except by means of this world.

Ali ibn Ibrahim (may Allah have mercy on him): قُولُوا قَوْلًا سَدِیداً [and speak the right word] means [speak] correct speech.