Praise is [due] to Allah, Lord of the worlds, Sustainer of the heavens and the earths, director of all created beings, sender of messengers, may Allah's praises and peace be upon them all, to responsible beings in order to guide them and clarify the ways of religion by means of decisive evidences and clear proofs. I praise Him for all His favors and ask Him for an excess of His bounty and generosity. I testify that there is no deity but Allah alone, there being no associate with Him – the One, the Prevailing, the Generous, the Perpetual Forgiver. And I testify that our master Muḥammad is His servant and messenger; His beloved and His pure friend; the best of creatures; the one honored through the mighty Qur’ān, the continuing miracle over the succession of years; and through sunnahs that enlighten those seeking right guidance; distinguished for comprehensive speech and ease in religion. May the blessings and peace of Allah be upon him and upon all the prophets and messengers, their families and all righteous people.  To proceed – it has been related to us from `Ali bin Abī Ṭālib, `Abdullāh bin Mas‘ūd, Mu‘ādh bin Jabal, Abūd-Dardā’, Ibn `Umar, Ibn ʽAbbās, Anas bin Mālik, Abū Hurayrah and Abū Sa`eed al-Khudri (may Allah be pleased with them) through numerous chains with varied narrations that the Messenger of Allah (ﷺ) said, "Whoever preserves for my nation forty ḥadīths concerning its religion – Allah will resurrect him on the Day of Resurrection among the jurists and scholars." In one narration it says, "...Allah will resurrect him as a jurist and scholar," and in that of Abūd-Dardā’, "...I will be for him, on the Day of Resurrection, an intercessor and a witness." In the narration of Ibn Mas‘ūd it says, "...he will be told, 'Enter by any of the doors of Paradise you wish,'" and in that of Ibn `Umar, "...he will be registered among the scholars and resurrected among the martyrs." But ḥadīth scholars have agreed that it is a weak ḥadīth despite its many narrations.  The scholars have compiled within this context countless collections. The first one I have known to do so was `Abdullāh bin al-Mubārak and then Ibn Aslam at-Tūsi, the nurturing scholar; then al-Ḥasan bin Sufyān an-Nasā’i, Abū Bakr al-Ajurri, Abū Bakr Muḥammad bin Ibrāheem al-Asfahāni, ad-Daraqutni, al-Ḥākim, Abū Nu`aym, Abū `Abdur-Raḥmān as-Sulami, Abū Sa‘eed al-Malīni, Abū ‘Uthmān as-Sabūni, `Abdullāh bin Muḥammad al-Anṣāri, Abū Bakr al-Bayhaqi and innumerable others from among  both previous and later ones. And I have made istikhārah to  Allah the exalted concerning the collecting of forty ḥadīthsfollowing the example of those well-known imams and preservers of Islam. For the scholars have agreed upon the permissibility of acting on a weak ḥadīth in regard to virtuous deeds. But in spite of this, my reliance is not upon that ḥadīth but rather on his ﷺ statement among the authentic hadiths: "Let the one present among you convey to the absent" and his saying: "May Allah make radiant [the face of] a person who heard my statement and grasped it and passed it on as he heard it." Then there were some scholars who collected forty [ḥadīths] on the fundamentals of the religion, while others [did so] on the derived matters, others on jihād, others on asceticism, others on conduct, others on speeches. And all of them are sound objectives, may Allah be pleased with those who intended them. But I have considered collecting forty more important than all of those, and they would be forty ḥadīths inclusive of all that, and each ḥadīth would be a great precept from those of the religion – one that scholars had described as having Islam revolve around it or half of Islam or a third of it and the like. Furthermore, I would commit myself, regarding these forty, to their being authentic, and most of them are [found] within the two Ṣaḥeeḥs of al-Bukhāri and Muslim. I cite them with the chains of narration removed in order to make their memorization easy and their benefit widespread, in-sha-Allah ta`ālā. I then them up with a section defining their more obscure wordings. Everyone desiring the Hereafter ought to know these ḥadīths for what they contain of important information and because they alert one to all acts of obedience [to Allah], which is clear to whoever reflects upon it. Upon Allah is my dependence, and upon Him is my relegation and support. To Him belongs [all] praise and favor, and from Him is [all] success and protection.