The Tahleel (Arabic: تَهْلِيل), also spelled Tahlil, is a form of dhikr that involves the praising of Allah (God) by saying lā ʾilāha ʾillā-llāhu (لَا إِلَٰهَ إِلَّا ٱللَّٰهُ), meaning "there is no true deity but Allah (God)".
This beautiful medley is presented by Ikhlaas Khan & Shaykh Sa’dullah Khan
Narrated by Abu Huraira: The Messenger of Allah said, "He who utters a hundred times in a day these words: 'La ilaha illallahu, wahdahu la sharika lahu, lahul-mulku wa lahul-hamdu, wa Huwa `ala kulli sha'in Qadir (there is nobody worthy of worship except Allah. He is One and He has no partner with Him; His is the sovereignty and His is the praise, and He is Omnipotent),' he will have a reward equivalent to that for emancipating ten slaves, a hundred good deeds will be recorded to his credit, hundred of his sins will be blotted out from his scroll, and he will be safeguarded against the devil on that day till the evening; and no one will exceed him in doing more excellent good deeds except someone who has recited these words more often than him." 1Sahih Muslim 2691; Book 48, Hadith 38
Malik ibn Anas reported from Talha ibn Ubaydullah ibn Kariz that the Messenger of Allah صلى الله عليه وسلم said, "The best dua is dua on the day of Arafa, and the best thing that I and the Prophets before me have said is "There is nothing worshipped but Allah, alone without any partner" (La ilaha illa'llah, wahdahu la sharika lah)" 2Muwatta Malik; Book 15, Hadith 32