Al-Matalib al-'Aliyah 2775 — Intellect and its virtue

It is narrated from Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Indeed, two men head for the mosque and offer the prayer there (in congregation); then one of them returns in such a state that his prayer is (in reward and worth) weightier than the mountain of Uhud, while the other returns in such a state that his prayer is not worth even the weight of a speck." At this Sayyiduna Abu Humayd al-Sa'idi (may Allah be pleased with him) said: (O Messenger of Allah!) How does this come about? He (peace and blessings be upon him) said: "When one of them is better than the other in intellect and understanding." He asked again: how is he (the one with better intellect)? He (peace and blessings be upon him) said: "When he is more scrupulous in avoiding the things Allah, the Mighty and Majestic, has forbidden, and more eager to hasten towards good deeds, even if he is less than him (the other man) in the abundance of voluntary worship."
The chain of this report contains Musa bin Ubaydah al-Rabadhi, whom the imams of narrator criticism declared weak; and Imam al-Bayhaqi recorded it in 'Shu'ab al-Iman'.