The Limits of Ablution, Its Order and Reward
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 11
وَقَالَ أَبُو جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ: «تَابِعْ بَيْنَ اَلْوُضُوءِ كَمَا قَالَ اَللَّهُ عَزَّ وَ جَلَّ اِبْدَأْ بِالْوَجْهِ ثُمَّ بِالْيَدَيْنِ ثُمَّ اِمْسَحْ بِالرَّأْسِ وَ اَلرِّجْلَيْنِ وَ لاَ تُقَدِّمَنَّ شَيْئاً بَيْنَ يَدَيْ شَيْءٍ تُخَالِفْ مَا أُمِرْتَ بِهِ فَإِنْ غَسَلْتَ اَلذِّرَاعَ قَبْلَ اَلْوَجْهِ فَابْدَأْ بِالْوَجْهِ وَ أَعِدْ عَلَى اَلذِّرَاعِ وَ إِنْ مَسَحْتَ اَلرِّجْلَ قَبْلَ اَلرَّأْسِ فَامْسَحْ عَلَى اَلرَّأْسِ ثُمَّ أَعِدْ عَلَى اَلرِّجْلِ اِبْدَأْ بِمَا بَدَأَ اَللَّهُ بِهِ.
Imam Muhammad ibn Ali Al-Baqir عليه السلام said: "Follow the sequence of wudu as Allah سبحانه وتعالى, Mighty and Majestic, has commanded. Start with the face, then the hands, then wipe the head and the feet. Do not precede anything before what you are commanded. If you wash the arm before the face, start with the face and then repeat on the arm. If you wipe the foot before the head, then wipe the head and then repeat on the foot. Begin with what Allah سبحانه وتعالى has started with." Similarly, in the adhan to Salat and the iqamah, start with the first (shahada) and then the second (shahada) and so forth. If you say: ‘Hasten to prayer (Hayya allas’Salat)’ before the testimonies, then you will again start with the testimonies and then repeat ‘Hasten to prayer.’"
- Ṣaḥīḥ al-Faqīh