Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
quran:18:24 –

Except ˹when adding˺, "If Allah wills." And remember your Lord when you forget ˹it˺ and say, "Perhaps my Lord will guide me to what is nearer than this to right conduct."  

without ˹adding˺, ‘If God will’, in other words, unless ˹firmly˺ adhering to the will of God, exalted be He, by saying, ‘If God will’ (inshā’a’Llāh). And remember your Lord, that is, ˹remember˺ His will, making ˹things˺ conditional on it, if you forget, to make ˹things˺ conditional on it: mentioning it after forgetting ˹it˺ is the equal ˹in validity˺ to mentioning it at the time of the statement — as al-Hasan ˹al-Basrī˺ and others have said — as long as the person is still in the ˹same˺ place ˹in which he made the statement˺. And say, ‘May be my Lord will guide me to ˹something˺ closer ˹in time˺ than this, ˹closer˺ than the story of the People of the Cave, as an indication of ˹the truth of˺ my prophethood, by way of guidance, and God indeed did so.
القرآن:١٨:٢٤ –

إِلَّا أَنْ يَشَاءَ اللَّهُ ۚ وَاذْكُرْ رَبَّكَ إِذَا نَسِيتَ وَقُلْ عَسَىٰ أَنْ يَهْدِيَنِ رَبِّي لِأَقْرَبَ مِنْ هَٰذَا رَشَدًا  

{إلا يشاء الله} أي إلا ملتبسا بمشيئة الله تعالى بأن تقول إن شاء الله {واذكر ربك} أي مشيئته معلقا بها {إذا نسيت} ويكون ذكرها بعد النسيان كذكرها مع القول الحسن وغيره ما دام في المجلس {وقل عسى أن يهدين ربي لأقرب من هذا} من خبر أهل الكهف في الدلالة على نبوتي {رشدا} هداية وقد فعل الله ذلك.