توحيد الألوهية
Abdullāh ibn Mas‘ūd (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: "Ruined are the extremists!." He said it thrice.
عن عبد الله بن مسعود -رضي الله عنه- أن رسول الله -صلى الله عليه وسلم- قال: "هلك المُتَنَطِّعون -قالها ثلاثا-".
شرح الحديث :
The Prophet (may Allah's peace and blessings be upon him) points out that delving deeply into certain matters and exceeding their proper bounds cause man's ruin. That is why he has forbidden this attitude. An example of that is when a man burdens himself with enormous acts of worship till he becomes averse to the worship and gives it up altogether. Another example is pretension in speech and using pompous words. The gravest type of extremism and the worthiest of being warned against is exceeding the proper bounds in venerating the righteous people in a way that leads to polytheism.