Those who said: it suffices him to draw a line in front of him when he prays

Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: If one of you prays in a desert or the like, he should set up his staff in front of him. If he has no staff, he should draw a line on the ground; then nothing passing in front of him will harm his prayer.
He said: (This is from) Abu al-Qasim (peace and blessings be upon him), meaning that he narrated it from the Prophet.

Ibrahim bin Maysarah said: When Tawus was leading the prayer and someone wanted to place something in front of him, he would forbid him.