Saying "If Allah wills" when determining to do Something in the Future

Here Allah, may He be glorified, shows His Messenger the correct etiquette when determining to do something in the future; this should always be referred to the will of Allah, the Knower of the Unseen, Who knows what was and what is yet to be and what is not to be, and how it will be if it is to be. It was recorded in the Two Sahihs that Abu Hurayrah said that the Messenger of Allah ﷺ said:

«قَالَ سُلَيْمَانُ بْنُ دَاوُدَ عَلَيْهِمَا السَّلَامُ: لَأَطُوفَنَّ اللَّيْلَةَ عَلَى سَبْعِينَ امْرَأَةً وَفِي رِوَايَةٍ: تِسْعِينَ امْرَأَةً، وَفِي رِوَايَةٍ: مِائَةِ امْرَأَةٍ تَلِدُ كُلُّ امْرَأَةٍ مِنْهُنَّ غُلَامًا يُقَاتِلُ فِي سَبِيلِ اللهِ، فَقِيلَ لَهُ وَفِي رِوَايَةٍ قَالَ لَهُ الْمَلَكُ: قُلْ إِنْ شَاءَ اللهُ، فَلَمْ يَقُلْ، فَطَافَ بِهِنَّ فَلَمْ تَلِدْ مِنْهُنَّ إِلَّا امْرَأَةٌ وَاحِدَةٌ نِصْفَ إِنْسَانٍ، فَقَالَ رَسُولُ اللهِصلى الله عليه وسلّم: وَالَّذِي نَفْسِي بِيَدِهِ، لَوْ قَالَ إِنْ شَاءَ اللهُ لَمْ يَحْنَثْ، وَكَانَ دَرَكًا لِحَاجَتِه»

Commentary

The story of Ashab al-Kahf is due to end on the four verses cited above. In the first two of these, the Holy Prophet ﷺ and his Ummah has been taught to say ` Insha'Allah Ta’ ala along with the promise or affirmation of doing something in the future. Because, who knows if one does or does not live, and even if one does, will one be able to do or not to do that? Therefore, a believer should be confident about it in his or her heart, and confess to it verbally as well that in the event of making a commitment to do something next day, what will be said will be: If Allah Ta` ala wills, I shall do this thing tomorrow.' This is what the saying of Insha'Allah means.