Man Lā Yaḥḍuruh al-Faqīh
Hadith 16803201 - إِذَا أَتَيْتَ اَلْفُرَاتَ فَاغْتَسِلْ وَ اِلْبَسْ ثَوْبَيْكَ اَلطَّاهِرَيْنِ ثُمَّ اِئْتِ اَلْقَبْرَ وَ قُلْ صَلَّى اَللَّهُ عَلَيْكَ يَا أَبَا عَبْدِ اَللَّهِ صَلَّى اَللَّهُ عَلَيْكَ يَا أَبَا عَبْدِ اَللَّهِ صَلَّى اَللَّهُ عَلَيْكَ يَا أَبَا عَبْدِ اَللَّهِ وَ قَدْ تَمَّتْ زِيَارَتُكَ هَذِهِ فِي حَالِ اَلتَّقِيَّةِ رَوَى ذَلِكَ يُونُسُ بْنُ ظَبْيَانَ عَنِ اَلصَّادِقِ عَلَيْهِ اَلسَّلاَمُ.
Hadith.3201 - When you arrive at the Euphrates River, perform ghusl (ritual purification), wear your two pure garments, and then proceed to the grave. Say:
"May Allah’s (swt) blessings be upon you, O Aba Abdillah.
May Allah’s (swt) blessings be upon you, O Aba Abdillah.
May Allah’s (swt) blessings be upon you, O Aba Abdillah."
With this, your visitation is complete under the condition of taqiyya (precautionary dissimulation).
This was narrated by Yunus ibn Zabyan from Imam Jafar ibn Muhammad Al-Sadiq (as).