الأنبياء والرسل السابقين عليهم السلام
Abu Sa‘īd al-Khudri (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "Mūsa (Moses) said: 'O my Lord, teach me something by which I mention You and invoke You.' Allah said: 'O Mūsa, say: 'there is no god but Allah'. Mūsa said: 'O my Lord, all Your slaves say that.' Allah said: 'O Mūsa, if the seven heavens and their inhabitants – other than Me – and the seven earths were placed on one side of the scale and 'there is no god but Allah' was placed on the other side, the scale would tip to the side with 'there is no god but Allah!''"
عن أبي سعيد الخدري -رضي الله عنه- عن رسول الله -صلى الله عليه وسلم- قال: "قال موسى: يا رب علمني شيئا أذكرك وأدعوك به، قال: قل يا موسى: لا إله إلا الله، قال: يا رب كل عبادك يقولون هذا، قال: يا موسى لو أن السموات السبع وعَامِرَهُنَّ غيري والأَرَضِينَ السبع في كِفَّةٍ، ولا إله إلا الله في كِفَّةٍ، مَالَتْ بهن لا إله إلا الله".
شرح الحديث :
Mūsa (peace be upon him asked his Lord, Glorified and Exalted, to teach him words of Dhikr by which he would praise Him and implore Him. So Allah directed him to say "there is no god but Allah". Mūsa realized that this Dhikr was frequently mentioned by people, and he wished to have a special Dhikr by which he would be distinguished from everyone else. Thereupon Allah, the Exalted, explained to him the great merit of this statement to which He guided him and that nothing is parallel to it. He told him that if that statement is placed on one side of the scale and the seven heavens and their inhabitants – apart from Allah – and the seven earths, great as they are, were placed on the other side, the scale would tip with "there is no god but Allah" because it is the basis of every religion and the foundation of every creed. This Hadīth is weak, but it is established that the testimony of faith - there is no god but Allah - is the most virtuous of words. Al-Bukhāri narrated that the Prophet (may Allah's peace and blessings be upon him) said: "The best of speech is four: Subhān Allah (Glory be to Allah), Al-Hamdulillah (Praise be to Allah), Lā ilāha illa Allah (There is no God but Allah), and Allah Akbar (Allah is Greatest)." Ahmad narrated from ‘Umar that he said: "The phrase that he (the Prophet) wanted his uncle to say was the the testimony of faith." Talhah said: "You have spoken the truth. If he had known a phrase more virtuous than it, he would have commanded him to say it."