Answered by Shaykh Abul ‘Ataa Ahmad Banaja (may Allah preserve him)
What is the ruling on saying “In Shaa Allaah ” (Allaah willing) for the things you want to do in the future?
Firstly and before answering your question, I would like to present you with an introduction to understand the cause and benefit of this beautiful statement (which is pronounced upon) the tongue of the Muslims.
Firstly, what is the reason why Muslims continously say the statement “Allaah willing,” in their words? The answer is because the Muslims believe that none knows the unseen except Allaah.
Allaah mentions this in the Qur’aan:
“قُل لَّا يَعْلَمُ مَن فِي السَّمَاوَاتِ وَالْأَرْضِ الْغَيْبَ إِلَّا اللَّـهُ ۚ وَمَا يَشْعُرُونَ أَيَّانَ يُبْعَثُونَ”
Say, “None in the heavens and earth knows the unseen except Allaah, and they do not perceive when they will be resurrected.” [Surah An-Naml 65]
So, if anyone is speaking about doing something in the future, without saying “In Shaa Allaah”, as if he is so certain about doing it so it becomes as if he knows the future “the unseen”. So, out of humbleness to Allaah, we say “In Shaa Allaah”, which means even though we are sure (in our intentions) to do the action, this can only occur after the permission of Allaah The Most High.
So, we come to know from this introduction that to saying “In Shaa Allaah” for future matters is obligatory, according to the most correct opinion. And this came clearly in a lot of evidences. Allaah جل وعلا mentioned in the Qur’aan:
“وَلَا تَقُولَنَّ لِشَيْءٍ إِنِّي فَاعِلٌ ذَٰلِكَ غَدًا إِلَّا أَن يَشَاءَ اللَّـهُ”
“And never say of anything, “Indeed, I will do that tomorrow.” Except [when adding], “If Allah wills.” [Surah Al-Kahf 23 – 24]
And as you see, this is an order to the prophet Muhammad ﷺ, what about us?!
Also Allaah The Most High said:
“لَّقَدْ صَدَقَ اللَّـهُ رَسُولَهُ الرُّؤْيَا بِالْحَقِّ ۖ لَتَدْخُلُنَّ الْمَسْجِدَ الْحَرَامَ إِن شَاءَ اللَّـهُ آمِنِينَ…”
“Certainly, has Allah showed to His Messenger the vision in truth. You will surely enter al-Masjid al-Haram, if Allah wills, in safety…” [Surah Al-Fath 27]
And it also comes in the two Sahihs from ‘Itban bin Maalik رضي الله عنه and others, that the Prophet ﷺ used to say “In Shaa Allaah.” And he used to say this, in many things that he wished to do in the future.
It also comes in the narration of Abu Hurairah, in the two Sahihs:
Allah’s Messenger (ﷺ) said, “(Prophet) Sulaiman once said, ‘Tonight I will sleep with ninety women, each of whom will bring forth a (would-be) cavalier who will fight in Allah’s Cause.” On this, his companion said to him, “Say: Allaah willing! (In Shaa Allaah)” But he did not say In Shaa Allaah. Sulaiman then slept with all the women, but none of them became pregnant but one woman who later delivered a half man. By Him in Whose Hand Muhammad’s soul is, if he (Sulaiman) had said, ‘Allaah willing’ (all his wives would have brought forth boys) and they would have fought in Allah’s Cause as cavaliers. ” [Sahih Al-Bukhari]
Sulaiman عليه السلام was a prophet, and Allaah accepts Du’a from the prophets. But when his companion reminded him to say, “In Shaa Allaah”, he forgot to say it. So, it didn’t happen, as a lesson from Allaah to teach us to connect everything we want to do in future with Allah’s will.
That’s why we say it is obligatory (to say In Shaa Allaah).
Even though, majority of the scholars say that saying “In Shaa Allaah” is Mustahabb (preferable), but the evidences from the Qur’aan and the Sunnah indicates to us that it is obligatory. So, considering these evidences, the most correct opinion is that saying “In Shaa Allaah” is obligatory .