Narrated Ibn Masud:

I was with the Prophet (ﷺ) at one of the farms of Medina while he was leaning on a date palm leaf-stalk. He passed by a group of Jews and some of them said to the other, Ask him (the Prophet) about the spirit. Some others said, "Do not ask him, lest he should tell you what you dislike" But they went up to him and said, "O Abal Qasim! Inform us bout the spirit." The Prophet (ﷺ) stood up for a while, waiting. I realized that he was being Divinely Inspired, so I kept away from him till the inspiration was over. Then the Prophet (ﷺ) said, "(O Muhammad) they ask you regarding the spirit, Say: The spirit its knowledge is with my Lord (i.e., nobody has its knowledge except Allah)" (17.85) (This is a miracle of the Qur'an that all the scientists up till now do not know about the spirit, i.e, how life comes to a body and how it goes away at its death) (See Hadith No. 245, Vol. 6)

Narrated `Abdullah:

While I was going with the Prophet (ﷺ) through the ruins of Medina and he was reclining on a date-palm leaf stalk, some Jews passed by. Some of them said to the others: Ask him (the Prophet) about the spirit. Some of them said that they should not ask him that question as he might give a reply which would displease them. But some of them insisted on asking, and so one of them stood up and asked, "O Abul-Qasim ! What is the spirit?" The Prophet (ﷺ) remained quiet. I thought he was being inspired Divinely. So I stayed till that state of the Prophet (while being inspired) was over. The Prophet (ﷺ) then said, "And they ask you (O Muhammad) concerning the spirit --Say: The spirit -- its knowledge is with my Lord. And of knowledge you (mankind) have been given only a little)." (17.85)

Narrated `Abdullah:

While I was walking with Allah's Messenger (ﷺ) in one of the fields of Medina and he was walking leaning on a stick, he passed a group of Jews. Some of them said to the others, "Ask him (the Prophet) about the spirit." Others said, "Do not ask him." But they asked him and he stood leaning on the stick and I was standing behind him and I thought that he was being divinely inspired. Then he said, "They ask you concerning the spirit say: The spirit, its knowledge is with My Lord. And of knowledge you (O men!) have been given only a little." ...(17.85) On that some of the Jews said to the others, "Didn't we tell you not to ask?"

Narrated Ibn Mas`ud:

While I was walking in company with the Prophet (ﷺ) in one of the fields of Medina, the Prophet (ﷺ) was reclining on a palm leave stalk which he carried with him. We passed by a group of Jews. Some of them said to the others, "Ask him about the spirit." The others said, "Do not ask him, lest he would say something that you hate." Some of them said, "We will ask him." So a man from among them stood up and said, 'O Abal-Qasim! What is the spirit?" The Prophet (ﷺ) kept quiet and I knew that he was being divinely inspired. Then he said: "They ask you concerning the Spirit, Say: The Spirit; its knowledge is with my Lord. And of knowledge you (mankind) have been given only a little." (17.85)