Assalaamu alaykum, Scholars. I would like to know what the status/reward/value of the voluntary prayers is. I am not refering to the Sunnah-prescibed ones, such as the Rawaatib, the night prayer, or the Duha prayer, but rather the prayers that one may make for instance between the Thuhr and the ‘Asr or between the Maghrib and the ‘Ishaa’. For instance, praying two or four or six or whatever Allah makes easy between the Thuhr and the ‘Asr or between the Maghrib and the ‘Ishaa’, which are permisbile times to pray, unlike after the Fajr and after the ‘Asr. Therefore, I hope you can quote some statements from the Salaf (pious predecessors). I hope my question is clear and you understand that I am not refering to the prescibed Sunnahs. An example of this could be Imam Ahmad ibn Hanbal, who, if I am not wrong, used to pray 300 units of prayer every day or something like this. And Allah knows best. May Allah bless you, Scholars.

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

Performing voluntary prayers (Naafilah) is one of the greatest acts of worship that draw the doer closer to Allah. It also makes up for any shortcomings in the obligatory prayers. The Prophet, sallallahu ‘alayhi wa sallam, said, “Prayer is the best legislated act of worship, so whoever can perform more prayers (beyond the obligatory ones), let him do so.” [At-Tabaraani - Al-Albaani graded it Hasan (good)]

It was narrated on the authority of Talhah ibn ‘Ubaydullah, may Allah be pleased with him, that a man from the people of Najd with unkempt hair came to the Messenger of Allah, sallallahu ‘alayhi wa sallam. We could hear him talking loudly, but we could not understand what he was saying until he came closer. He was asking about Islam. The Messenger of Allah, sallallahu ‘alayhi wa sallam, said to him, “Five prayers each day and night.” He said, “Do I have to do anything else?” He said, “No, unless you do it voluntarily...’” [Al-Bukhaari, Muslim, and others]

Ma‘daan ibn Abi Talhah, may Allah be pleased with him, said:

“I met Thawbaan, the freed slave of the Messenger of Allah, sallallahu ‘alayhi wa sallam, and asked him to tell me about a deed which, if I were to do it, Allah would admit me to Paradise (or he said: about the deed that is most beloved to Allah). He gave no reply. I asked again, and he gave no reply. I asked him for the third time, and he said, ‘I asked the Messenger of Allah, sallallahu ‘alayhi wa sallam, about that, and he said, 'Make frequent Sujood (prostration in prayer); for every time you make Sujood to Allah, He will raise you in status one rank and erase one sin from you.'’”[Muslim]

The Prophet, sallallahu ‘alayhi wa sallam, said, “The first deed for which a person will be held accountable on the Day of Resurrection will be his prayers. If they are in order, he will have prospered and succeeded; and if they are lacking, he will have failed and lost. If there is something missing in his obligatory prayers, the Lord Almighty will say, ‘See if My servant has any voluntary prayers with which to complete the deficiency in his obligatory prayers. And then the rest of his deeds will be judged in like manner.’” [Ibn Maajah and At-Tirmithi]

Al-Mulla ‘Ali Al-Qaari wrote, “The hadeeth reads, 'Prayer is the best legislated act of worship...' It means that it is the best of all deeds that Allah prescribed for His slaves to draw closer to Him.” [Sharh Al-Mishkaah]

Az-Zarqaani wrote, “The hadeeth: ‘The best of your deeds is prayer,’ means that it is the most rewardable of your deeds. Therefore, prayer is considered the best deed, as it includes many acts of worship, such as reciting the Quran, Tasbeeh (saying: Sobhaan Allah [glory be to Allah]), Tahleel (saying: La ilaaha ill-Allah [there is nothing worthy of worship but Allah]), Takbeer (saying: Allahu Akbar [Allah is the Greatest]), refraining from (idle) talk, and the acts that invalidate the fasting and so on...” [Sharh Al-Muwatta’]

Allah knows best.