It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that whenever he intended to touch the Black Stone (istilam), he would say: 'Allahumma imanan bika wa tasdiqan bi-kitabika wa sunnati nabiyyika sallallahu 'alayhi wa sallam' (O Allah, (I do this) believing in You, affirming Your Book, and following the Sunnah of Your Prophet (peace and blessings be upon him)). Then he would touch it.
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Nafi' except Muhammad bin Muhajir, and Awn bin Sallam is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الميم / 5843
Hadith Takhrij«أخرجه الطبراني فى «الأوسط» برقم: 5486»