What is the meaning of minor shirk, major shirk, hidden shirk, and subtle shirk?

Question:
What is the meaning, O Shaykh, of minor shirk and major shirk, and hidden shirk and subtle shirk?

Answer:
On the surface, shirk has types:
Major shirk is well known: worshipping idols, attaching oneself to statues, calling upon the dead, and seeking aid from the dead. All of this is apparent major shirk.
And among it is what is subtle: what is in the hearts of riya' (showing off), and seeking the praise and commendation of people. One may worship, or pray, or fast, or recite in front of people, and his secret in his heart is that they should praise him and commend him. He may recite for that reason, or he may go to places to be praised for going to them, such as circles of knowledge, or distant mosques, to pray in them, not for the sake of the Face of Allah, but for riya'.
So shirk (associating partners with Allah) involves subtle matters in the hearts that only the Knower of the Unseen (Glorified and Exalted is He) knows, such as types of riya' (showing off in worship); therefore, in another hadith—the hadith of Abu Sa'id—it is said: We said: Yes, O Messenger of Allah. He said: , and in the other wording: .
So the summary is: that shirk has the hidden, and the apparent, the subtle, and the major:
So the subtle is what is in the hearts, what is in some words that people do not notice.
And apparent shirk is what people see and hear: such as calling upon the dead, seeking aid from the dead, cursing Islam, criticizing Islam, and cursing the prophets. These are clear things. We ask Allah for safety.
And what is of hidden shirk: such as what may be confused for people, such as: "What Allah willed and so-and-so willed," "If not for Allah and the Prophet," and "the trust." This is hidden from some people, and they do not notice that it is shirk. For this reason, swearing by other than Allah and saying "What Allah willed and so-and-so willed" often occurs in people's speech, due to their ignorance and lack of knowledge.