A Muslim must follow only what God revealed in the SCRIPTURES. We must understand this fact: The Messengers and Prophets bring ONLY what was given to them, and they share that with mankind, period. A messenger does not bring any additional information that is outside of what Allah inspired them to share with people. Prophet Muhammad was given the Quran Alone and NOTHING else, see 6:19. Moses was given the Scripture & Furqan, see 2:53. Jesus received and brought down the Gospels(Injiil), see 57:27 and David brought down the Psalms(Zubuur), see 4:163. People must understand, that Messengers, the human, must also follow & OBEY THE MESSENGER of God, and they must follow and obey the instructions, and God's commandments the same way we do. No difference, see 80:1-2. Also, 33:37.
If they disobey, they will be punished just like anyone or even harsher. See (69:44-46).
The problem is that mankind, does not value God as He should be valued, and they
associate their Creator with His messengers, such as Jesus, Muhammad or some other Saints. We forget Satan's promise to God. That he will mislead all mankind. He certainly succeeded in doing that today unfortunately, just look at the world around us everywhere! The death, the hate, the destruction, the division, the disasters, the idol worship, and evil everywhere you look. Jesus and Prophet Muhammad are more revered and admired instead of God.
We forget that messengers were just simple human beings, who ate the same food we eat, they cried, laughed, got thirst and hungry, got sick, and faced everyday problems that we face. But they persevered and stayed loyal to God Alone. When we do the same, we obey them wholeheartedly. Anyone who wants to know the history of God's messengers, and wants to obey and follow them, must not look anywhere outside of the Quran. Allah explained EVERYTHING in the Quran, see 6:114.
Read, obey, and ponder on the following Quranic verses. That is what obeying the Rasuul means:
Then we inspired you (Muhammad) to follow the religion of Abraham, the monotheist; he never was an idol worshiper. 16:123
ثُمَّ أَوْحَيْنَا إِلَيْكَ أَنِ اتَّبِعْ مِلَّةَ إِبْرَاهِيمَ حَنِيفًا ۖ وَمَا كَانَ مِنَ الْمُشْرِكِينَ
O you who believe, you shall embrace total submission; do not follow the steps of Satan, for he is your most ardent enemy. 2:208
يَا أَيُّهَا الَّذِينَ آمَنُوا ادْخُلُوا فِي السِّلْمِ كَافَّةً وَلَا تَتَّبِعُوا خُطُوَاتِ الشَّيْطَانِ ۚ إِنَّهُ لَكُمْ عَدُوٌّ مُّبِينٌ
O people, eat from the earth's products all that is lawful and good, and do not follow the steps of Satan; he is your most ardent enemy. 2:168
يَا أَيُّهَا النَّاسُ كُلُوا مِمَّا فِي الْأَرْضِ حَلَالًا طَيِّبًا وَلَا تَتَّبِعُوا خُطُوَاتِ الشَّيْطَانِ ۚ إِنَّهُ لَكُمْ عَدُوٌّ مُّبِينٌ
Eat from GOD's provisions to you, and do not follow the steps of Satan; he is your most ardent enemy. 6:142
وَمِنَ الْأَنْعَامِ حَمُولَةً وَفَرْشًا ۚ كُلُوا مِمَّا رَزَقَكُمُ اللَّهُ وَلَا تَتَّبِعُوا خُطُوَاتِ الشَّيْطَانِ ۚ إِنَّهُ لَكُمْ عَدُوٌّ مُّبِينٌ
You shall all follow what is revealed to you from your Lord; do not follow any idols(Prophets, Messengers, Saints, Ulema, etc.) besides Him. Rarely do you take heed. 7:3
اتَّبِعُوا مَا أُنزِلَ إِلَيْكُم مِّن رَّبِّكُمْ وَلَا تَتَّبِعُوا مِن دُونِهِ أَوْلِيَاءَ ۗ قَلِيلًا مَّا تَذَكَّرُونَ
O you who believe, do not follow the steps of Satan. Anyone who follows the steps of Satan, should know that he advocates evil and vice. If it were not for GOD's grace towards you, and His mercy, none of you would have been purified. But GOD purifies whomever He wills. GOD is Hearer, the Knower. 24:21
يَا أَيُّهَا الَّذِينَ آمَنُوا لَا تَتَّبِعُوا خُطُوَاتِ الشَّيْطَانِ ۚ وَمَن يَتَّبِعْ خُطُوَاتِ الشَّيْطَانِ فَإِنَّهُ يَأْمُرُ بِالْفَحْشَاءِ وَالْمُنكَرِ ۚ وَلَوْلَا فَضْلُ اللَّهِ عَلَيْكُمْ وَرَحْمَتُهُ مَا زَكَىٰ مِنكُم مِّنْ أَحَدٍ أَبَدًا وَلَٰكِنَّ اللَّهَ يُزَكِّي مَن يَشَاءُ ۗ وَاللَّهُ سَمِيعٌ عَلِيمٌ