It wasnarrated that Ibn 'Umar said:
"When the Prophet (ﷺ) prayedonthe day of 'Eid or on another occasion, a small spear was set up infront of him, and he prayed facing it, and the people were behindhim."Nafi` said: It is from here that the leaders have taken this practice.
English reference: Vol. 1, Book 5, Hadith 1305
Arabic reference: Book 5, Hadith 1365