"And your garments, purify [them]" (Wa-thiyabaka fa-tahhir). Qatada's interpretation: Do not wear them while committing disobedience against Me. It is said of a righteous man that he is 'pure of garments.'
﴿وثيابك فطهر﴾ تَفْسِيرُ قَتَادَةَ: لَا تَلْبَسْهَا عَلَى مَعْصِيَتِي، وَيُقَالُ لِلرَّجُلِ الصَّالِحِ: إِنَّهُ لطاهر الثِّيَاب