Muhammad is not the father of any of your men, but the Messenger of Allah and the final seal of the prophets. Allah has knowledge of all things. (Surat al-Ahzab, 40)
As is stated in the above verses, the Prophet Muhammad (saas) is the last prophet. Through the verses that begin with "Say”, Allah conveyed to our Prophet (saas) what needed to be said to people. Through these verses, our Prophet (saas) communicated Allah's message.
The Prophet Muhammad (saas) said that those who fear Allah and seek to be forgiven, should follow him:
Say, “If you love Allah, then follow me and Allah will love you and forgive you for your wrong actions. Allah is Ever-Forgiving, Most Merciful.” (Surah Al ‘Imran, 31)
This call of the Prophet Muhammad (saas) still applies universally. Allah enjoined strict obedience on the messengers He sent, and in many verses, states that obedience to the messengers is, in actuality, obedience to Allah.
The Prophet (saas) also stressed the importance of obedience in the hadiths:
“Whoever obeys me, obeys Allah, and whoever disobeys me, disobeys Allah, and whoever obeys the ruler I appoint, obeys me, and whoever disobeys him, disobeys me.” (Sahih Bukhari)
For this reason, obedience to the messenger is at the heart religion and showing this obedience surely comes about through strict submissiveness to the issues conveyed by messengers.