Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
The command to say “InshAllah” (if Allah wills) is mentioned when a Muslim informs others of his determination to do something in the future.
Answering your question, the Fatwa Center at Islam Q and A, states:
The command to say “InshAllah” (if Allah wills) is mentioned when a Muslim informs others of his determination to do something in the future.
Allah, the Most High, says: “And never say of anything, “I will definitely do this tomorrow without adding, “InshAllah (if Allah so wills)!” But if you forget, then remember your Lord, and say, “I trust my Lord will guide me to what is more right than this.'” (Al-Kahf 18:23-24)
Al-Tabari (may Allah have mercy on him) said: “This is a disciplinary measure from Allah, the Exalted, who instructed His Prophet (peace be upon him) not to assert decisively about future matters as definite occurrences unless connected with Allah’s will, because nothing happens except by His will.” [Tafsir Al-Tabari, 15/223]
Al-Wahidi (may Allah have mercy on him) said: “The commentators said: This is Allah’s disciplinary action towards His Prophet (peace be upon him) commanding him to use the exception clause when determining something by Allah’s will. If you say about something, ‘I will do it tomorrow,’ then say, ‘InshAllah.'” [Al-Basit, 13/581]
Ibn Al-Jawzi (may Allah have mercy on him) said: “Once Solomon, son of David said, ‘(By Allah) Tonight I will have sexual intercourse with one hundred (or ninety-nine) women each of whom will give birth to a knight who will fight in Allah’s Cause.’ On that a (i.e. if Allah wills) but he did not say, ‘Allah willing.’ Therefore only one of those women conceived and gave birth to a half-man. By Him in Whose Hands Muhammad’s life is, if he had said, “Allah willing’, (he would have begotten sons) all of whom would have been knights striving in Allah’s Cause.”
If a man from the people of Gog and Magog says, ‘Tomorrow, we will dig the dam, InshAllah,’ it will benefit them, and they will be able to dig!”
“When a Prophet missed his intended purpose by omitting the phrase ‘InshaAllah’, and a disbeliever achieved his intended purpose by saying it, its importance should be recognized. How not, when it indicates the helplessness of humanity and the submission of the matter to the Lord of all dominion.” [Kashf al-Mushkil min Hadith al-Sahihayn, 2/27]
Abu al-Abbas al-Qurtubi (may Allah have mercy on him) said regarding the story of Solomon (peace be upon him): “And His statement, ‘Say: InshAllah,’ this is a reminder for him to say it with his tongue, not that he neglected to entrust it to Allah Almighty in his heart. It is far from the Prophets and unworthy of their exalted positions and continuous knowledge. This is similar to what has been agreed upon regarding our Prophet (peace be upon him) when asked about the soul, al-Khidr, and Dhu al-Qarnayn, he promised to bring the answer tomorrow, affirming his knowledge of Allah Almighty, confirming his promise, and showing his word. However, he refrained from speaking the word ‘InshAllah,’ not from entrusting it to Allah Almighty in his heart, so he was disciplined by the delay of revelation until he was accused of lying for it.
Indeed, Allah Almighty taught and disciplined His Prophet by saying: “And never say of anything, ‘Indeed, I will do that tomorrow,’ except [when adding], ‘ InshAllah ‘…”. This is due to the lofty positions of the Prophets and their perfect knowledge of Allah Almighty, wherein they are admonished and held accountable for what others are not admonished for. As the Prophet (peace be upon him) said regarding prophet Lot: “May Allah have mercy on Lot, he was dwelling near a severe corner,” rebuking him for uttering a word that could be permissible for others to say. [Al-Mufhim, 4/637]
Sheikh Abd al-Rahman al-Sadi (may Allah have mercy on him) said:
“This prohibition, like others, though directed specifically to the Messenger (peace be upon him) is general for all accountable individuals. Allah has forbidden His servant from stating decisively about future matters (‘Indeed, I will do that’) without coupling it with ‘ InshAllah ‘. This is because of the dangers inherent in such speech, which involve talking about the unseen future, about which one does not know whether it will happen or not, and whether one will be able to do it or not. This leads to attributing the outcome solely to the servant’s own will, which is forbidden, because all matters are in the hands of Allah (‘And you do not will except that Allah wills, the Lord of the worlds’).”
“The mention of Allah’s will brings about facilitation, blessings, and seeking assistance from one’s Lord. Due to human fallibility, one may forget to mention Allah’s will. Therefore, Allah commanded to make an exception afterwards if it is mentioned, so that the desired outcome is achieved and the harms are avoided.” [Tafsir al-Sadi, p. 474]
Read also:
Saying InshAllah after Making Dua
Almighty Allah knows best.
Source: IslamQA.Info