Shirk: Third Principle
There is no difference between one who worships stones, pious people, sun and moon, angels, etc. They are in the same boat of shirk
Humans have taken different gods through the years, and their offspring have adopted similar practices. Some have chosen to raise idols made out of stones as their god, others have taken people (prophets, saints, etc) alive or buried in the ground, and some chose celestial objects and others unseen beings like angels. And of His signs are the night and day and the sun and moon. Do not prostrate to the sun or to the moon, but prostate to Allah, who created them, if it should be Him that you worship. [Quran 41:37] Allah and His Messenger (pbuh) have not distinguished between any of them as they all are committing shirk. The beings they are misplacing their worship for need Allah, and are in the same shoes as us, they rely upon Him just like us.
If we take a moment to ponder that everything that exists is merely a creation of Allah, created effortlessly without any reduction over His Dominion, and everything that happens is a realization of His Will, then should we not ask how can worshiping another creation help us in any way, be it as a means of getting close to Him, wanting His love and mercy, or having our prayers answered. And they (the prophets) did not order you that you take the angels and the prophets as gods. [Quran 3:80]
Praying to anyone or anything besides Allah is not accepted by our Lord. Tawheed (Oneness of Allah) is the key to seeking His pleasure, while shirk is a means of being led astray.
And [beware the Day] when Allah will say, "O Jesus, Son of Mary, did you say to the people, 'Take me and my mother as deities besides Allah ?'" He will say, "Exalted are You! It was not for me to say that to which I have no right. If I had said it, You would have known it. You know what is within myself, and I do not know what is within Yourself. Indeed, it is You who is Knower of the unseen. [Quran 5:116]