Muwatta Malik, Book 20, Hadith 114 (USC-MSA) ⓘ

Yahya related to me from Malik from Hisham ibn Urwa that his father said that the Messenger of Allah, may Allah bless him and grant him peace, once said to Abd ar-Rahman ibn Awf, "What do you do, Abu Muhammad, when saluting the corner?" and Abd ar-Rahman said, "Sometimes I salute it, and sometimes I don't." The Messenger of Allah, may Allah bless him and grant him peace, said, "You are right."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّهُ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لِعَبْدِ الرَّحْمَنِ بْنِ عَوْفٍ ‏"‏ كَيْفَ صَنَعْتَ يَا أَبَا مُحَمَّدٍ فِي اسْتِلاَمِ الرُّكْنِ ‏"‏ ‏.‏ فَقَالَ عَبْدُ الرَّحْمَنِ اسْتَلَمْتُ وَتَرَكْتُ ‏.‏ فَقَالَ لَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ أَصَبْتَ ‏"‏ ‏.‏