Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: When a person leaves his seat in a gathering and then returns, he is more entitled to that place.
Hadith Takhrij«أخرجه مسلم: 2179 ، (انظر مسند أحمد ترقيم الرسالة: 10823 ترقیم بيت الأفكار الدولية: 10835»
Brief Explanation
Benefits: … Some worshippers have been observed coming to the mosque before preparing for prayer—such as using the miswak (tooth-stick), performing ablution (wudu), and cleansing oneself (istinja)—and placing a cloth or some other item in the first row, then leaving. Afterwards, they consider themselves entitled to that spot. This manner is not correct, because the person who comes fully prepared and sits down even once, that place becomes his right. There is no point in placing a marker or the like without coming prepared.