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:54:50 –

And Our command is but one, like a glance of the eye.  

And Our command, for a thing which We want to bring into existence, is but a single word, like the twinkling of an eye, in terms of speed, and this is the saying of kun, ‘Be’, whereat it comes into existence. His command, when He wills a thing, is just to say to it ‘Be’, and it is ˹Q. 36:82˺.
القرآن:٥٤:٥٠ –

وَمَا أَمْرُنَا إِلَّا وَاحِدَةٌ كَلَمْحٍ بِالْبَصَرِ  

{وما أمرنا} لشيء نريد وجوده {إلا} مرة {واحدة كلمح بالبصر} في السرعة وهي قول: كن فيوجد (إنما أمره إذا أراد شيئا أن يقول له كن فيكون).