يوفونَ بِالنَّذرِ وَيَخافونَ يَومًا كانَ شَرُّهُ مُستَطيرًا

They fulfil their vows and fear a day whose ill will be widespread.

EXEGESIS

Nadhr (vow) is a promise to perform an act of piety or goodness (birr) if one’s wish is realised or one’s fear is prevented.^{‎[1]Tibyan, 10/209; Razi, 30/744-745; Tabari, 29/129.} Once made, one is held accountable before God to fulfil it (22:29, 16:91).^{‎[2]Razi, 30/745.}

Mustaṭīr (widespread) means to be sweepingly widespread. Judgement Day is being qualified with such widespread ill because its horrors and agonies will be at their highest peak.^{‎[3]Mizan, 20/126.}

INSIGHTS FROM HADITH

1. Regarding they fulfil their vows, Uṣūl al-Kāfī reports that Imam al-Sajjād (a) said: ‘[It refers to the children of Adam who] fulfil their vows to hold firm to our guardianship (wilāyah), as part of their covenant with God.’^{‎[4]Kafi, 1/434, h. 91.}

Note: this hadith is outside the boundaries of conventional exegesis (tafsīr) and comes under allegorical interpretation (taʾwīl) which is a special class of Quranic interpretation reserved for God and those firmly grounded in knowledge (3:7). For more detail about the covenant, refer to verse 7:172. This hadith provides insight in two ways. First, it emphasises that although the verses came in honour of the Ahl al-Bayt, they are applicable to anyone who embodies these virtues. Second, being true to these virtues is to be devoted to those who embody them most perfectly. Hence, Allah called upon humankind to hold firm to the guardianship of the Messenger of God and the infallible Imams from his progeny because they are the only ones capable of leading humankind towards a global realisation of these ideals.

[1] Tibyan, 10/209; Razi, 30/744-745; Tabari, 29/129.
[2] Razi, 30/745.
[3] Mizan, 20/126.
[4] Kafi, 1/434, h. 91.