Allah subhanahu wa ta’ala says in Surah Isra Ayah 78 – 79: “Establish prayer at the decline of the sun [from its meridian] until the darkness of the night and [also] the Qur’an of dawn. Indeed, the recitation of dawn is ever witnessed.”
Abu Hurayra radhiAllahu anhu reports that the Messenger of Allah salAllahu alayhi wa sallam was asked, “What prayer is most virtuous, after the obligatory prayers?” He said, “Prayer in the depths of the night.” [Muslim, Abu Dawud, Tirmidhi, Nasa’i, Ibn Majah]
Abu Umama al-Bahili radhiAllahu anhu reports that the Messenger of Allah said, “Hold fast to night prayer, for it was the way of the righteous before you, a way of drawing closer to your Lord, an expiation for wrong deeds, and a shield from sin.” [Tirmidhi, and others] In some narrations, there is an addition, “And it repels sickness from the body.”
Ibn Mas`ud radhiAllahu anhu said, “The virtues of night prayer over day prayer is like the virtue of secret charity over open charity.” [Tabarani] The scholars explain that this refers to voluntary prayers.
Imam Saffarini, the Hanbali faqih and sufi, explained in his Sharh Mandhumat al-Adaab:
“Night prayer is superior to day prayer because:
– It is more concealed and closer to sincerity. The righteous early Muslims (salaf) used to strive hard to hide their secrets [i.e. the actions between them and Allah].
– Hasan [al-Basri] said, ‘It used to be that a person would have guests staying over and he would pray at night without his guests knowing…’
– Night prayer is harder on the lower self, because night is a time of rest from the tire of day, so leaving sleep despite the lower self being desirous of it is a tremendous struggle (mujahada). Some have said, ‘The best of works are those the lower self is forced to perform.’
– Recitation in night prayer is closer to contemplation, because things that busy the heart are mostly absent at night, so the heart is attentive and is with the tongue in understanding, as Allah Most High said, ‘o! The night vigil is (a time) when impression is more keen and speech more certain. Allah subhanahu wa ta’ala says in Surah Al-Muzzamil: “Indeed, the hours of the night are more effective for concurrence [of the heart and tongue] and more suitable for words. Indeed for you by day is prolonged occupation.” It is because of this that we have been commanded to recite the Qur’an in night prayer in a steady recital (tartil).
– Night prayer is a shield from sins
– Night vigil time is the best of times for voluntary worship and prayer, and the closest a servant is to his Lord.
– It is a time when the doors of the sky are opened, supplications answered, and the needs of those who ask fulfilled.
Allah subhanahu wa ta’ala has praised those who wake up at night for His remembrance, supplication, and to seek forgiveness and entreat Him, saying, “They forsake their beds to cry unto their Lord in fear and hope, and spend of what We have bestowed on them. No soul knows what is kept hid from them of joy, as a reward for what they used to do.” [Qur’an, 32: 16-17]
The scholars derived the following from the Qur’an and prophetic ahadith:
1. The minimal night vigil prayer is 2 rakats. [Hindiyya, quoting Fath al-Qadir]
2. Its optimal recommended amount is 8 rakats, because this was the general practice of the Messenger of Allah sallalahu aalyhi wa sallam. [Hindiyya, quoting Fath al-Qadir]
3. Lengthier recitation is superior to a larger number of rakats prayed. [Durr al-Mukhtar, Radd al-Muhtar]
4. If one divides the night in thirds, then the final middle third is most virtuous. [Durr al-Mukhtar]
5. If one divides the night in half, then the second half is more virtuous. [ibid.]
6. Voluntary (nafl) prayer at night is more virtuous than voluntary prayer during the day. However, the full reward mentioned in the Qur’anic verses and Prophetic hadiths refers to worship that was preceded by sleep. This is also understood from the very linguistic meaning of tahajjud, which is to struggle rid oneself of sleep. [Ibn Abidin, Radd al-Muhtar, quoting Ibn Amir Haajj’s Halba]
7. It is disliked to leave the night vigil prayer for one who has made it their habit, unless there is an excuse, because the Prophet Muhammad sallalahu aalyhi wa sallam said to Ibn Umar (Allah be pleased with him), “O Abd Allah! Do not be like so-and-so. He used to pray at night and then left it.” [Bukhari and Muslim]
Therefore, one should take on an amount of works one can sustain, for the Messenger of Allah said,“The most beloved of actions to Allah are the most constant, even if little.” [Bukhari and Muslim] [Ibn Abidin, Radd al-Muhtar, from Ibn Amir Haajj’s Halba]
8. It is recommended to start the night vigil with two short rakats, because of the hadith of Abu Hurayra that the Prophet Muhammad said, “It you get up for night prayer, start with two short rakats.” [Muslim, Ahmad, Abu Dawud]
9. Supplications in the depths of the night are answered, as the hadiths have mentioned.
Ibn Mas`ud (Allah be pleased with him) was asked, ‘I cannot pray at night.’ He said, ‘Your sins have prevented you.’
(Excerpt [with slight modifications] from an article shared at muslimvillage.com]