It is narrated from Sayyiduna Ali (may Allah be pleased with him) that whenever he touched the Black Stone (istilam), he would say: 'Allahumma imanan bika, wa tasdiqan bi-kitabika, wa ittiba'an sunnata nabiyyika (peace and blessings be upon him)' (O Allah, (I do this) believing in You, affirming the truth of Your Book and following the Sunnah of Your Prophet (peace and blessings be upon him)).
We do not know of any hadith other than this that Abu al-Umays (may Allah have mercy on him) narrated with a connected chain from Abu Ishaq (may Allah have mercy on him). No one narrated it from Abu al-Umays (may Allah have mercy on him) except Hafs (may Allah have mercy on him), and no one narrated it from Hafs (may Allah have mercy on him) except Ibrahim al-Shafi'i (may Allah have mercy on him).
Hadith Referenceالمعجم الأوسط / باب الألف / 492
Hadith Gradingمحدثین:إسناده ضعيف لضعف الحارث
Hadith Takhrij«قال الهيثمي: وفيه الحارث وهو ضعيف وقد وثق «مجمع الزوائد ومنبع الفوائد، ج 3، ص 240»» «أخرجه البيهقي فى «السنن الكبرى» برقم: 9343، 9344، والطيالسي فى «مسنده» برقم: 174، وابن حجر فى «المطالب العالية» برقم: 1221، وابن أبي شيبة فى «مصنفه» برقم: 16045، 16046، 30245»