In the name of Allah, the Beneficent, the Merciful
Al-Nawawi records in his book Riyad us-Saliheen:
Allah the Exalted said:
فَمَاذَا بَعْدَ الْحَقِّ إِلَّا الضَّلَالُ فَأَنَّىٰ تُصْرَفُونَ
What can be beyond truth except error? So how are you averted?
Surah Yunus 10:32
And Allah said:
مَّا فَرَّطْنَا فِي الْكِتَابِ مِن شَيْءٍ
We have not neglected anything in the Book.
Surah Al-An’am 6:38
And Allah said:
يَا أَيُّهَا الَّذِينَ آمَنُوا أَطِيعُوا اللَّهَ وَأَطِيعُوا الرَّسُولَ وَأُولِي الْأَمْرِ مِنكُمْ ۖ فَإِن تَنَازَعْتُمْ فِي شَيْءٍ فَرُدُّوهُ إِلَى اللَّهِ وَالرَّسُولِ إِن كُنتُمْ تُؤْمِنُونَ بِاللَّهِ وَالْيَوْمِ الْآخِرِ ذَٰلِكَ خَيْرٌ وَأَحْسَنُ تَأْوِيلًا
O you who believe, obey Allah and obey the Messenger and those in authority among you. If you disagree over anything, refer it to Allah and the Messenger if you believe in Allah and the Last Day. That is the best way and best in result.
Surah An-Nisa 4:59
And Allah said:
وَأَنَّ هَٰذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوهُ وَلَا تَتَّبِعُوا السُّبُلَ فَتَفَرَّقَ بِكُمْ عَن سَبِيلِهِ ذَٰلِكُمْ وَصَّاكُم بِهِ لَعَلَّكُمْ تَتَّقُونَ
This is My straight path, so follow it and do not follow other ways for you will be separated from His way. This has He instructed you that you may become righteous.
Surah Al-An’am 6:153
And Allah said:
قُلْ إِن كُنتُمْ تُحِبُّونَ اللَّهَ فَاتَّبِعُونِي يُحْبِبْكُمُ اللَّهُ وَيَغْفِرْ لَكُمْ ذُنُوبَكُمْ وَاللَّهُ غَفُورٌ رَّحِيمٌ
Say: If you love Allah, then follow me so Allah will love you and forgive your sins, for Allah is Forgiving and Merciful.
Surah Ali Imran 3:31
And Allah said:
قُلْ مَا كُنتُ بِدْعًا مِّنَ الرُّسُلِ وَمَا أَدْرِي مَا يُفْعَلُ بِي وَلَا بِكُمْ إِنْ أَتَّبِعُ إِلَّا مَا يُوحَىٰ إِلَيَّ وَمَا أَنَا إِلَّا نَذِيرٌ مُّبِينٌ
Say: I am not something new among the messengers, nor do I know what will be done with me or with you. I only follow that which is revealed to me and I am not but a clear warner.
Surah Al-Ahqaf 46:9
Aisha reported: The Messenger of Allah, peace and blessings be upon him, said:
مَنْ أَحْدَثَ فِي أَمْرِنَا هَذَا مَا لَيْسَ فِيهِ فَهُوَ رَدٌّ
Whoever innovates something into this affair of ours which does not belong to it will have it rejected.
Source: Sahih Bukhari 2550, Grade: Muttafaqun Alayhi
In another narration, the Prophet said:
مَنْ عَمِلَ عَمَلًا لَيْسَ عَلَيْهِ أَمْرُنَا فَهُوَ رَدٌّ
Whoever performs a deed that is not in accordance with our matter will have it rejected.
Source: Sahih Muslim 1718, Grade: Sahih
Al-Irbad ibn Sariya reported: One day the Messenger of Allah, peace and blessings be upon him, stood up among us and he admonished us so eloquently that it moved our hearts and made tears come from our eyes. It was said, “O Messenger of Allah, you have given us a farewell sermon, so enjoin a covenant upon us.” The Prophet said:
أُوصِيكُمْ بِتَقْوَى اللَّهِ وَالسَّمْعِ وَالطَّاعَةِ وَإِنْ عَبْدٌ حَبَشِيٌّ فَإِنَّهُ مَنْ يَعِشْ مِنْكُمْ يَرَى اخْتِلَافًا كَثِيرًا وَإِيَّاكُمْ وَمُحْدَثَاتِ الْأُمُورِ فَإِنَّهَا ضَلَالَةٌ فَمَنْ أَدْرَكَ ذَلِكَ مِنْكُمْ فَعَلَيْهِ بِسُنَّتِي وَسُنَّةِ الْخُلَفَاءِ الرَّاشِدِينَ الْمَهْدِيِّينَ عَضُّوا عَلَيْهَا بِالنَّوَاجِذِ
You must fear Allah, listen to and obey your leaders even if an Abyssinian slave is put in charge over you. After me you will see violent differences and so you must adhere to my tradition (sunnah) and the tradition of the upright, guided successors. Bite onto it with your teeth and beware of newly invented matters. Verily, every newly invented matter is an innovation and every innovation is misguidance.
Source: Sunan At-Tirmidhi 2676, Grade: Sahih
Success comes from Allah, and Allah knows best.