What is the ruling on a man praying without covering his head with anything?

The student : This is one of the sessions I used to hold regarding the head covering in...

The Shaykh : May Allah have mercy on you.
The student : ...in the prayer.

The Shaykh : ...regarding?
The student : ...regarding the head covering, or wearing a cap, or placing anything on the head during the prayer...
Another student: Brothers, whoever does not have books from these, please take...
Another student: So the brothers in Riyadh said: It is permissible for you to pray without a cap, and... we heard a tape of yours, I believe, in which you said that you do not permit, you do not permit the prayer without...

The Shaykh : ...a head covering.
The student : ...This, our Shaykh, do you remember when I came from Saudi Arabia and went to America, I asked you a question because I told you: I understood that you say it is not permissible to pray without the cap, andThe Shaykh : Adnan and Dr. Basim said no, andThe Shaykh : may Allah reward him with good, and he clarified that to me.

The Shaykh : ...My brother, we do not say "not permissible" in the sense that the common people understand, but we say: It is part of the etiquette of prayer to stand before Allah in the most complete form. Why? Because of a hadith and an athar. As for the hadith, it is His saying (peace and blessings be upon him): , . The izār is the upper cloth that the pilgrim wears, excuse me, the rida' (cloak), the izār is the lower one. The Messenger (peace and blessings be upon him) said: Whoever has these two garments, let him wear the rida' and let him wear the izār, for Allah has more right to be adorned for than anyone else.
And Allah (Mighty and Majestic) says in the Noble Qur'an: . The reason for the revelation of this verse is that the polytheists in the pre-Islamic age of ignorance used to circumambulate the Ka'bah naked, claiming a pre-Islamic custom, which is from the inspiration of Satan, without doubt. They used to say: "Allah (Mighty and Majestic) is too great for us to circumambulate His House in clothes in which we have disobeyed Allah." So they would strip naked, saying: My Lord, as You created me. Even the woman, look how great is the scheme of Satan against mankind, even the woman would enter the Sacred Mosque—Allah knows where this came from—throw off her clothes, and circumambulate while doing this, reciting and saying:
"Today some of it is revealed, or all of it *** And what is revealed of it, I do not make it lawful"
This is from the inspiration of Satan. So when the Qur'an came and this verse was revealed in it, He (Glorified and Exalted is He) said: ; meaning: Cover your private parts. Then the Wise Lawgiver, through the tongue of His Noble Prophet, expanded the indication of this verse to a meaning other than the meaning for which the verse was revealed. The verse was revealed regarding covering the major private part, which for the man is what is between the navel and the knee. But there is a minor private part, which is what is above the navel; therefore he (peace and blessings be upon him) said in this hadith: , and there are other hadiths that we are not concerned with now. I said at the beginning of my speech that there is a hadith and an athar. Most scholars say that if the Muslim prays covering his private part, his prayer is valid and permissible, but it is disliked. Why? He prays like this, with his body exposed. Yes, this is not a private part, but and so on. Rather, there is something greater than this, and this is what some scholars say, and he (peace and blessings be upon him) said: ; meaning: Either he prays as mentioned in the previous hadith with a rida' that covers the shoulders, as the pilgrim does, except during the tawaf where he exposes his shoulder, but other than the tawaf he covers his shoulders. If he has a rida' and an izār, he uses both garments. But if he has only one garment, if the garment is wide and loose, he covers himself with it from above to below the knee, and thus he has prayed having covered his shoulders, due to his saying (peace and blessings be upon him): .
The student : ...In the single garment, our Shaykh, is there a problem or not? In the single garment, let no one of you pray in a single garment with nothing on his shoulders?

The Shaykh : ...That is , but the detail is what we are saying: He has a rida' and an izār, so he must wear the rida' and wear the izār. He has only one garment, if it is wide, he (peace and blessings be upon him) said: . So in the case of a narrow garment, the prayer is valid even if the upper part is exposed. But if he has a second garment, a rida', or if he has a wide garment to wrap himself in, and he prays with his shoulders exposed, the upper part exposed, the Messenger prohibits this prayer . We have known this.
We come to the head covering. Here is an athar and here is fiqh. As for the athar, it is what Ibn Taymiyyah (may Allah have mercy on him) mentioned in a beautiful treatise of his on the clothing of the woman or the hijab of the woman in prayer. He mentioned that Ibn 'Umar saw his slave Nafi' praying with nothing on his head. After the prayer, he called him and said: .
And as you see, the committed Muslims still maintain covering the head as an Islamic etiquette. As for this exposure that has spread today among the young Muslims, this is one of the effects of European colonialism when these lands were colonized by Britain, and Syria by France, and so on. These are among their customs, to expose their heads. As for the old Muslims, they cover their heads either with a cap or a turban. Do you see? This is the Islamic etiquette. We say that the Muslim prays in the most complete form. It does not mean that it is not permissible to pray like this. No, I myself sometimes pray like this, but many times I intend to take the cap and put it on my head, holding fast to this Islamic etiquette. Perhaps it has become clear to you?
The student : May Allah reward you with good.

The Shaykh : And beware of that.