Is one who does not prostrate at the place of prostration while reciting the Qur’an sinful, and is prostration obligatory?

The prostration of recitation (Sujud al-Tilawah) is a Sunnah; the one who performs it is rewarded, and the one who leaves it is not sinful, based on the saying of Umar, may Allah be pleased with him: "Indeed, Allah has not enjoined prostration upon us, unless we wish to."