If a Muslim wasn't used to pray and then he started and never left a prayer, does he need to pray all prayers he has previously left or Allah (Subhanahu wa Ta'ala) will forgive him?
According to some of the scholars (Ibn Hazm, some of the Shafi'is, Ibn Taymiyyah and the modern salafis), no, he does not need to make them up. This is because none of the companions, tabi'een, etc. ever made them up; there is no explicit ayah of Qur'an, or hadith of rasulullah (peace be upon him) telling us to make up prayers we missed.
In fact, this is a serious issue to consider: A missed prayer cannot be made up, ever. It's missed. Forever. You can see this fatwa on Islam-QA as one reference.
As mentioned in @AlUmmat's answer, he should make tawbah (sincere repentance) for what he did wrong, and move forward by praying on time, every time.
If the issue is someone accidentally skipping a prayer, such as if they set their alarms for Fajr (early morning) prayers and slept through, then the scholars mention that they must make it up as soon as they remember (i.e. wake up enough to realize they missed it). This is from the hadith:
Allah's Messenger said: "Whoever forgets a Salat then he is to pray it when he remembers it." (Sahih) Recorded in At-Tirmidhi
If someone intentionally leaves an obligatory prayer (i.e. salah) without any valid excuse: Then the position of the majority of the scholars, including the four Sunni schools, is that they must make up such prayers (i.e. perform them now, after their due time).
أجمع العلماء الذين يعتد بهم على أن من ترك صلاة عمدا لزمه قضاؤها
There is consensus of the scholars whose opinion counts that whoever leaves a prayer intentionally must make it up.
واختلفوا في وجوب القضاء على تارك الصلاة عمدا ... فأما المتعمد في الترك، فيرى جمهور الفقهاء أنه يلزمه قضاء الفوائت ... ويرى بعض الفقهاء عدم وجوب القضاء على المتعمد في الترك، قال عياض: ولا يصح عند أحد سوى داود وابن عبد الرحمن الشافعي
The opinion of the majority of the jurists is that qada is obligatory on the one who deliberately misses a prayer ... and the opinion of some of the jurists is that it is not obligatory, and 'Iyad said: This is not correct near anyone except Dawood and Ibn Abdur Rahman al-Shafi'i.
The Quranic verses that command us to perform Salah, such as:
And establish prayer
These verses categorically command us to perform salah, and there is no evidence which waives this command just because the time has run out. Hence delaying it will earn sin but the command must be still be carried out.
من نسي صلاة فليصل إذا ذكرها، لا كفارة لها إلا ذلك
If anyone forgets a prayer he should pray that prayer when he remembers it. There is no expiation except that.
Because the meaning of نسي (forgets) is also inclusive of neglecting or leaving something intentionally, see almaany and there are examples of this usage with the Quran such as 9:67 where it is used in the meaning of intentional disregard.
Further it is supported by analogy, since if an expiation (Qada) is due on a person who is blameless then it is even more fitting that it be due on a person who is guilty of willful neglect.
Based on generalization of the hadith below where an obligatory acts of worship has been compared to a debt and where it is prescribed to make up for it if it has been delayed beyond its due time:
قاضية اقضوا الله، فالله أحق بالوفاء
So, pay Allah's debt as He has more right to be paid.
While there is a minority position that such a person does not have to make up the missed salah, rather he can only repent, ask for pardon from Allah, and perform supererogatory prayers and other good deeds. This opinion was held by the Zahiris (including Dawood al-Zahiri, Ibn Hazm), some individuals from the Shafi'is, Ibn Taymiyyah and some others. And in modern times this opinion is held by the Salafis.
Their evidence is that the Quran and Ahadith provide a set time for each prayer and they have claimed that it is not valid to perform the obligatory prayers at any other time without explicit evidence - and no such evidence exists for the case of a person who deliberately leaves Salah. The only exceptions which are proven are for those who have missed salah because of an excuse such as because they were asleep or because it slipped from their mind.
Regardless of the above, it is agreed upon that missing salah without any valid excuse is a great sin and you must do sincere tawabah. Allah will incha'Allah forgive you ... But remember that no one can be sure that his tawbah is sincere enough, and remember that Allah has said in the Quran:
نَبِّىءْ عِبَادِي أَنِّي أَنَا الْغَفُورُ الرَّحِيمُ
وَ أَنَّ عَذَابِي هُوَ الْعَذَابُ الأَلِيمَ
(15:49) _"Tell My servants that I - I alone - am truly forgiving, a true dispenser of grace;" (15:50) "and [also,] that the suffering which I shall impose [on sinners] will indeed be a suffering most grievous."
Scholars say that tawbah (repentance) requires all of the following:
- immediate renunciation of the sin
- firm intention and determination to not return to the sin ever again,
- regret over having committed a sin
- compensating for it if the sin was against the rights of another human being (stealing something, swearing at someone, breaking something etc.) - Huququl 'ibaad = right of Allah's servant
I will suggest to you to take your time and to do this at a slow pace that you can easily sustain. There's no need to complete all of your pending prayers immediately since it will be difficult and will demoralize you. You should rather be steady and consistently perform a small amount every day, even one prayer qada every day. Another good way to manage this is to do Qada for one salah before every obligatory prayer in a day.
For more information, have a look at:
Note: you only have to make up missed salah from the time you became muslim (if you are a convert to islam) or since bulugh (puberty).
In fact a missed prayer cannot be made up, ever. It's missed for forever.
According to the majority of scholars, no, he does not need to make them up. This is because none of the Companions, Tabi'een, etc. ever made them up; there is no explicit ayah of Qur'an, or hadith of Rasulullah (peace be upon him) telling us to make up prayers we missed. Imam Nawawi refers to the hadith related by Anas that the Messenger of Allah (Allah bless him and give him peace) said, “Whoever forgets a prayer must perform it when they remember it…” [Bukhari (597), and Muslim (684).
Prayers missed in life time will only be made up through true and sincere repentance from Almighty Allah Who is Ever Forgiving, Ever Merciful. Qaza Umri for the lifetime missed prayers in reality discourage people from performing prayers due to fear of past guilt. Remember, Allah, the Almighty is so GREAT that HE Forgives all your sins even if you bring a mountain full of your sins, provided you seek forgiveness truly and sincerely from the core of your heart.
In the name of God, the Beneficent, the Merciful
All perfect praise be to God, the Lord of the worlds. I testify that there is none worthy of worship except God and that Muhammad ￼ is His slave and Messenger.
Your question: Does a Muslim have to pray all the prayers that he left out?
Answer: Yes, you can. But you must make a clear intention as follows: “I’m performing such and such day’s Fajr prayer (for example).
If you have missed so many prayers that you don’t remember the exact number of prayers missed then the intention should be made as follows: “oh God! From those prayers I have missed, I am performing the first Fajr Salaah (for example)”. Likewise a person should try to roughly remember how many prayers he/she has to make up for and make up for them as soon as possible until content that all missed prayers are performed.
Why should a person make up his or her lost prayers due to laziness?
Because, no one knows when death will come upon him or her, so better be prepared. Do your homework (by praying, trying to recover the lost prayers, do good etc..) so that you can pass the final exam (the Day of Judgment)
the messenger of God (peace and blessings be upon him) mentions:
Whenever one of you misses a prayer due to sleeping or due to negligence, it is obligatory upon him/her that he/she pray the prayer when he remembers it because God has metioned, “Perform prayer when you remember me”(Muslim,Hadith 1569)