What is meant by showing off (riya'), and when does it become minor shirk (associating partners with Allah), and when does it become major shirk?

Question:
May Allah reward you with good and do you good. One of the listeners sent a message containing a collection of questions, and he asks you, Shaykh Salih, specifically about showing off (riya'). He says: What is meant by showing off? When does it become minor shirk? When does it become major shirk? And if a person finds some of it in his heart while performing a certain act of worship and says the famous supplication, "O Allah, I seek refuge in You from associating anything with You that I know, and I seek Your forgiveness for what I do not know," is this the wording that was transmitted? We ask for clarification and explanation of it. And when is this supplication recited if it is inside the prayer? May Allah reward you with good.

Answer:
Riya' (showing off in worship) is when a person wants people to see his deeds and worship so that they praise him and speak well of him. This is riya'. If it mixes with the deed, it invalidates it from its root. If the riya' was present from the very beginning of the act of worship, then the worship is not valid because it is founded on riya'. However, if a person began the worship with sincerity and then riya' crept in, if he persists with it, it invalidates the deed. But if he repels it, abandons it, and returns to sincerity, then it does not harm him, if Allah wills. The bottom line is that riya' is dangerous, and it is shirk (associating partners with Allah), as the Prophet (peace and blessings be upon him) said: He was asked about it, and he said: "Riya'." It is hidden shirk, and it invalidates the deed it mixes with, according to the details we have mentioned. So a person must repel it. This supplication: "O Allah, I seek refuge in You from associating anything with You while I know it, and I seek Your forgiveness for the sin I do not know," is said outside of prayer. It is said outside of prayer. As for in prayer, he must repel the riya' and return to sincerity for Allah (Mighty and Majestic), and keep in mind the greatness of Allah (Mighty and Majestic). Yes.