It was narrated from Ibn Umar concerning the Messenger of Allah (ﷺ) he said: "He used to set up a short spear then pray facing toward it."
Sunan an-Nasa'i Book 9, Hadith 6
← Previous Hadith "The messenger of Allah(ﷺ) was asked during the campaign of Tabuk about the Sutra of one who is praying. He said: "Something as high as the back of a camel saddle."

Sunan an-Nasa'i Book 9, Hadith 5 Next Hadith → "When anyone of you prays toward a Sutra, let him get close to it and not allow the Shaitan to sever his prayer for him."

Sunan an-Nasa'i Book 9, Hadith 7