Al-Kāfi - Volume 1 > Chapter on al-Ruh, the Spirit
Hadith #3

3ـ مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنْ مُحَمَّدِ بْنِ خَالِدٍ عَنِ الْقَاسِمِ بْنِ عُرْوَةَ عَنْ عَبْدِ الْحَمِيدِ الطَّائِيِّ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ قَالَ سَأَلْتُ أَبَا عَبْدِ الله (عَلَيْهِ السَّلام) عَنْ قَوْلِ الله عَزَّ وَجَلَّ وَنَفَخْتُ فِيهِ مِنْ رُوحِي كَيْفَ هَذَا النَّفْخُ فَقَالَ إِنَّ الرُّوحَ مُتَحَرِّكٌ كَالرِّيحِ وَإِنَّمَا سُمِّيَ رُوحاً لانَّهُ اشْتَقَّ اسْمَهُ مِنَ الرِّيحِ وَإِنَّمَا أَخْرَجَهُ عَنْ لَفْظَةِ الرِّيحِ لانَّ الارْوَاحَ مُجَانِسَةٌ لِلرِّيحِ وَإِنَّمَا أَضَافَهُ إِلَى نَفْسِهِ لانَّهُ اصْطَفَاهُ عَلَى سَائِرِ الارْوَاحِ كَمَا قَالَ لِبَيْتٍ مِنَ الْبُيُوتِ بَيْتِي وَلِرَسُولٍ مِنَ الرُّسُلِ خَلِيلِي وَأَشْبَاهِ ذَلِكَ وَكُلُّ ذَلِكَ مَخْلُوقٌ مَصْنُوعٌ مُحْدَثٌ مَرْبُوبٌ مُدَبَّرٌ.

3. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from Muhammad ibn Khalid from Qasin ibn ‘Urwa from ‘Abd al-Hamid al- Ta’i from Muhammad ibn Muslim who has said the following. “I asked Imam abu ‘Abdallah (a.s.) about the words of Allah, the Most Holy, the Most High, ‘I have blown My Spirit into it (15:29)’” The Imam (a.s.) replied, “The spirit has motion like winds. It is called spirit (Ruh) because the word is a derivative of Rih (wind). This derivative is selected because the spirits are similar or are of the genus of the Rih (wind). He has given His own possessive case because He selected it from among the other spirits just as He has said about a House from among the houses ‘My house’ and to a messenger from among the messengers ‘My friend’ and so on. All such things are created, invented, newly produced and are cherished by the Lord.”