It is narrated from Sayyiduna Abu al-Rudayn (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whenever people gather over the Book of Allah and study it together among themselves, they are the guests of Allah and the angels surround them, until they get up or become occupied with some other talk. And whenever a servant goes out in search of knowledge for fear that it (the knowledge) may die away, or goes out to copy it for fear that it may be effaced, he is like one who goes forth morning and evening in the path of Allah. And whoever is held back by his deeds, his lineage will not advance him."
Hadith Referenceالمعجم الكبير للطبراني / مسند من يعرف بالكنى / 19047