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. (DE)
English reference (DE): Vol. 1, Book 5, Hadith 1305 (DE)
Arabic reference (DE): Book 5, Hadith 1365 (DE)