The real work of the Prophet is to be an exponent of the truth (shaahid, as translated by Shah Waliullah). He should clearly show who will be entitled to God’s Grace and who will deserve punishment from God in the eternal life after death.
The rising of such a ‘shaahid’ or witness of Truth poses the greatest trial for his addressees. They have to hear God’s voice in the voice of a human being. They have to see a representative of God in the shape of a human being. While giving their hand into the hands of a man, they have to think that they are giving their hand into the hands of God. For those who prove to have this superior insight, God has great rewards in store, but to those who fail in this test, God will mete out the most severe punishment.
If a person says I am a Muslim, then being a Muslim he declares that he is God's spokesperson, God's representative.
This is called shuhada in the Quran: Copy arabic text (22:78)
The ummat-e-Muhammad is shahid, or God's representative. Shahid means one who bears witness.
A hadith says: Copy arabic text (Sahih al-Bukhari 2642)
All this is very clearly written in the Quran and Hadith. Thinking about this, I realized that this task of bearing witness is called dawah. Dawah and shahadah are the same.
The Quran says: Copy Arabic text (85:3)
The Quran uses shahid and mashhud. This is same as dayee and madu. In the Quran, shahid and mashhud are same as dayee and madu. According to the Quran, we believe that messengers came in every age and did dawah work.
The Prophet Muhammad was the final Prophet. After him, no other prophet is going to come.
What is the reason? Why did God do this?
This is not anything mysterious. Reflecting on this, I realized that in earlier ages dawah was done in a personalized way. A person came as a prophet. He did dawah work and then passed away. Then another prophet came. He also did dawah and then died. According to the Hadith, about 1 lakh prophets were sent to the world. This was an age of doing dawah in a personalized way. This means dawah was done by an individual. After the Prophet Muhammad, a new age came. The Prophet of Islam brought a new revolution in history. The Prophet was born at the dawn of a new era in history. This was the beginning of the scientific era.
What is the scientific era?
Scientific age means the age of communication, globalization, global interaction and so on. This is a new age which didn’t exist in previous times. The Prophet came at the beginning of this new age. This age was one of globalization and universalization. After the Prophet, dawah work will happen in an institutionalized way. Earlier, dawah happened in a personalized way. Now it would happen in an institutionalized way. After the Prophet's death, his community is in the position of prophethood. This means that the entire community, as an institution, has to perform the task which an individual prophet did in earlier times.