What is the ruling on a man praying without a sutra, regardless of whether he knows it is obligatory or not?

The prayer is valid without a sutrah, whether the worshiper knows of its obligation or not, and whether someone passes in front of him or not. However, the prayer is susceptible to deficiency if someone passes in front of the worshiper, and the worshiper's reward decreases in proportion to his negligence of the Sunnah.