All praise be to Allah, the Lord of the worlds, and peace and blessings be upon our Prophet Muhammad, the truthful and honest one, and upon all his family and Companions!
Allah (Glorified and Exalted be He) sent Prophets and Messengers to invite people to Tawhid (belief in the Oneness of Allah), to sincerely worship Allah Alone, and to explain the Shar'iah (Islamic Law) that He ordained for His Servants. He created humans and Jinn (creatures created from fire) for this purpose.
And I (Allâh) created not the jinn and mankind except that they should worship Me (Alone).
And verily, We have sent among every Ummah (community, nation) a Messenger (proclaiming): "Worship Allâh (Alone), and avoid (or keep away from) Tâghût (all false deities i.e. do not worship Tâghût besides Allâh)."
Allah (Glorified be He) says that He never punishes a people until after He has sent them a bearer of good news and a warner.
O people of the Scripture (Jews and Christians)! Now has come to you Our Messenger (Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭﺳﻠﻢ) making (things) clear unto you, after a break in (the series of) Messengers, lest you say: "There came unto us no bringer of glad tidings and no warner." But now has come unto you a bringer of glad tidings and a warner. And Allâh is Able to do all things.
And We never punish until We have sent a Messenger (to give warning).
Our Prophet Muhammad (peace be upon him), whom Allah commissioned after a period of suspension of Messengers, received the Wahy (Divine Revelation) when
oppression and disobedience of Allah prevailed on earth, to bring people back to obedience of Allah. He (peace be upon them) was sent to both the Jinn and humans, Arabs and nonArabs, as a bearer of good news and a warner and to inform people of Allah's Shar'iah. He (peace be upon him) explained AlHaqq (the Truth) and invited people to adhere to it, sending envoys and letters to leaders and kings to call them to Islam, to establish the inexcusable evidence against those who reject and oppose his Da'wah (calling to Islam).
Say (O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭﺳﻠﻢ): "O mankind! Verily, I am sent to you all as the Messenger of Allâh to Whom belongs the dominion of the heavens and the earth. Lâ ilâha illa Huwa (none has the right to be worshipped but He). It is He Who gives life and causes death. So believe in Allâh and His Messenger (Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭﺳﻠﻢ), the Prophet who can neither read nor write (i.e. Muhammad ﺻـﻠﻰ ﺍﷲ ﻋﻠﻴـﻪ ﻭﺳـﻠﻢ), who believes in Allâh and His Words [(this Qur'ân), the Taurât (Torah) and the Injeel (Gospel) and also Allâh's Word: "Be!" and he was, i.e. 'Isâ (Jesus) son of Maryam (Mary), ﻋﻠﻴﻬﻤﺎ ﺍﻟﺴﻼﻡ], and follow him so that you may be guided."
Allah made the Shari'ah he gave to the Prophet (peace be upon him) the last of the Shari'ahs and made his Message the last of all the Messages, possessing absolute perfection and comprehensiveness, to set people's affairs aright in this world and the Hereafter. The Prophet (peace be upon him) guided the people to all good and warned them against every evil.
I have left you on white (clear) proof; its night is like its day. None shall deviate from it after me except that he is destroyed.
There was never a prophet before me except that it was a duty upon him that he should guide his Ummah (nation based on one creed) towards every good he knew for them and warn them against every evil he knew for them.
(Related by Muslim in his "Sahih [Book of Authentic Hadith]")
I have left you two matters, that if you hold onto you will never go astray: the Book of Allah and the Sunnah of His Prophet.
The Qur'an enjoins da'wah (calling people to Islam), to the din (Religion) of Allah, which is the Din of Al Haqq (the Truth), and no other Din except it shall be accepted by Allah from humans.
Invite (mankind, O Muhammad ﺻﻠﻰ ﺍﷲ ﻋﻠﻴﻪ ﻭ ﺳﻠﻢ) to the Way of your Lord (i.e. Islâm) with wisdom (i.e. with the Divine Revelation and the Qur'ân) and fair preaching, and argue with them in a way that is better.
Truly, the religion with Allâh is Islâm.
And whoever seeks a religion other than Islâm, it will never be accepted of him, and in the Hereafter he will be one of the losers.
The Sunnah (whatever is reported from the Prophet) also encourages Da'wah and explains the duty of Muslims towards the Din of allah. They are required to explain Islam to all people, as it is an Amanah (trust) placed on the shoulders of the Muslim scholars, and they will not be freed from the obligation of explaining it and advising both Muslims and nonMuslims.
A Mu'min (believer) to another Mu'min is like a building, each part supporting the other.
(Related by AlBukhari and Muslim)
The similitude of the Mu'mins as regards their mutual love, mercy, and empathy is that of a body; when any part of it suffers, the whole body calls upon one another (sharing) with (it) sleeplessness and fever.
(Agreed upon by AlBukhari and Muslim)
Anyone who guides to good will have a reward like that of the one who does it.
(Related by Muslim in his "Sahih")
It was also reported in the Two Sahih Books of Hadith (i.e. AlBukhari and