The Sutra - Section 2 Mishkat al-Masabih 783

Arabic hadith text
وَعَنِ الْمِقْدَادِ بْنِ الْأَسْوَدِ قَالَ: مَا رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُصَلِّي إِلَى عُودٍ وَلَا عَمُودٍ وَلَا شَجَرَةٍ إِلَّا جَعَلَهُ عَلَى حَاجِبِهِ الْأَيْمَنِ أَوِ الْأَيْسَرِ وَلَا يصمد لَهُ صمدا. رَوَاهُ أَبُو دَاوُد
Translation

Al-Miqdad b. al-Aswad said, “I never saw God’s Messenger praying in front of a stick, a pillar, or a tree, without having it opposite his right or left eyebrow (i.e. side), and not facing it directly.” Abu Dawud transmitted it.