The Messenger of Allah ﷺ heard a man saying: O Allah, I ask Thee, I bear witness that there is no god but Thou, the One, He to Whom men repair, Who has not begotten, and has not been begotten, and to Whom no one is equal, and he said: You have supplicated Allah using His Greatest Name, when asked with this name He gives, and when supplicated by this name he answers.  

أَنَّ رَسُولَ اللَّهِ ﷺ سَمِعَ رَجُلاً يَقُولُ اللَّهُمَّ إِنِّي أَسْأَلُكَ أَنِّي أَشْهَدُ أَنَّكَ أَنْتَ اللَّهُ لاَ إِلَهَ إِلاَّ أَنْتَ الأَحَدُ الصَّمَدُ الَّذِي لَمْ يَلِدْ وَلَمْ يُولَدْ وَلَمْ يَكُنْ لَهُ كُفُوًا أَحَدٌ فَقَالَ لَقَدْ سَأَلْتَ اللَّهَ بِالاِسْمِ الَّذِي إِذَا سُئِلَ بِهِ أَعْطَى وَإِذَا دُعِيَ بِهِ أَجَابَ  

“The Prophet ﷺ heard a man supplicating, and he was saying: ‘O Allah, indeed, I ask you by my testifying that You are Allah, there is none worthy of worship except You, the One, As-Samad, the one who does not beget, nor was begotten, and there is none who is like Him (Allāhumma innī as’aluka bi annī ashhadu annaka antallāh, lā ilāha illā ant, al-aḥaduṣ-ṣamad, alladhī lam yalid wa lam yūlad, wa lam yakun lahu kufuwan aḥad).” He said: “So he said: ‘By the One in Whose Hand is my soul, he has asked Allah by His Greatest Name, the one which if He is called upon by it, He responds, and when He is asked by it, He gives.’”(One of the narrators) Zaid said: “So I mentioned it to Zuhair bin Muʿawiyah years after that, and he said: Abu Ishaq reported to me from Malik bin Mighwal.’” Zaid said: “Then I mentioned it to Sufyan, so he reported it to me from Malik.”  

سَمِعَ النَّبِيُّ ﷺ رَجُلاً يَدْعُو وَهُوَ يَقُولُ اللَّهُمَّ إِنِّي أَسْأَلُكَ بِأَنِّي أَشْهَدُ أَنَّكَ أَنْتَ اللَّهُ لاَ إِلَهَ إِلاَّ أَنْتَ الأَحَدُ الصَّمَدُ الَّذِي لَمْ يَلِدْ وَلَمْ يُولَدْ وَلَمْ يَكُنْ لَهُ كُفُوًا أَحَدٌ قَالَ فَقَالَ وَالَّذِي نَفْسِي بِيَدِهِ لَقَدْ سَأَلَ اللَّهَ بِاسْمِهِ الأَعْظَمِ الَّذِي إِذَا دُعِيَ بِهِ أَجَابَ وَإِذَا سُئِلَ بِهِ أَعْطَى قَالَ زَيْدٌ فَذَكَرْتُهُ لِزُهَيْرِ بْنِ مُعَاوِيَةَ بَعْدَ ذَلِكَ بِسِنِينَ فَقَالَ حَدَّثَنِي أَبُو إِسْحَاقَ عَنْ مَالِكِ بْنِ مِغْوَلٍ قَالَ زَيْدٌ ثُمَّ ذَكَرْتُهُ لِسُفْيَانَ الثَّوْرِيِّ فَحَدَّثَنِي عَنْ مَالِكٍ  

"The Prophet (saas) heard a man say: 'Allahumma! Inni as'aluka bi-annaka Antallahul-Ahadus-Samad, alladhi lam yalid wa lam yuwlud, wa lam yakun lahu kufuwan ahad (O Allah! I ask You by virtue of Your being Allah, the One, the Self-Sufficient Master, Who begets not nor was begotten, and there is none co-equal or comparable to Him).' The Messenger of Allah (saas) said: 'He has asked Allah by His Greatest Name, which if He is asked thereby He gives, and if He is called upon thereby He answers.'" (Using translation from Ibn Mājah 3857)  

أَنَّ النَّبِيَّ ﷺ سَمِعَ رَجُلًا يَقُولُ اللهُمَّ إِنِّي أَسْأَلُكَ بِأَنَّكَ أَنْتَ اللهُ الْأَحَدُ الصَّمَدُ الَّذِي لَمْ يَلِدْ وَلَمْ يُولَدْ وَلَمْ يَكُنْ لَهُ كُفُوًا أَحَدٌ فَقَالَ رَسُولُ اللهِ ﷺ لَقَدْ سَأَلَ اللهَ بِاسْمِهِ الْأَعْظَمِ الَّذِي إِذَا سُئِلَ بِهِ أَعْطَى وَإِذَا دُعِيَ بِهِ أَجَابَ