What was prophet Muhammad’s(s.a.w.) first message at the mosque? What did prohpet Muhammad (s.a.w.) say to the muslims? The description of the first and second sermon in the mosque…
THE FIRST SERMON
“Repent before death! Perform good deeds while the opportunity is at hand! By offering plenty of charity, secretly or openly, and by constantly remembering Allah, mend your relations with Allah! Do this and you shall be blessed, assisted and be made to regain all that you have lost.
“Know that on this month of this year, in this place, Allah has made obligatory the Friday Salat. May his ends never meet, who takes the Salat lightly or abandons it in rejection, while there is an imam, just or unjust, to lead him, while I am still alive or after me! And may Allah never guide him to success! Such a person has no other salat (in hope of acceptance)—except those who repent, for Allah will accept their repentance.” (Ibn Majah, Iqamah, 78)
“Prepare for your Hereafter while you have your health! Death will surely come to pass and leave your flocks without a shepherd. Then without a translator or a medium, Allah will ask:
‘Has not my Prophet come to you and informed you of My commands? For all the wealth you had and My favors upon you, what have you brought today for yourself?’
“Faced with this question each person will look left and right to no avail; then they will look to the front and see Hellfire.
“So wake up! Guard yourselves from the flames, even if it be with half a date! If you cannot even find half a date, then with kind words; for a single goodness is multiplied by ten to seven hundred times.
“May Allah’s blessings and mercy be upon you!” (Ibn Hisham, I, 118-119, Bayhaqi, Dalail, II, 524)
The Second Sermon
“Praise be to Allah. Only from Him do I seek help. His protection we seek from the evils of our own souls and the wickedness of our deeds. Whoever Allah guides nobody shall misguide and nobody can guide whoever He causes to deviate.
“I bear witness that there is no god but Allah. He is one, without partner. The most beautiful words are in His Book. Whosoever’s heart Allah has adorned with the Quran and guided him to Islam after darkness, has been salvaged, if he chooses the Quran above all words.
“The book of Allah is truly the most beautiful and eloquent of words.
“Love what Allah loves! Do not ever be weary of Allah’s word and His remembrance! Do not let your hearts strain from the word of Allah, for His words pick and choose from the best. They explain the best deeds, and give mention to the Prophets, the most eminent of servants, and convey the most beautiful and striking accounts. It makes explicit the permissible and the non-permissible.
“Worship only Allah and do not ascribe any partners to Him! Fear Him the way He ought to be feared! Have your tongues support your good deeds! Love each other with the word of Allah! Know that Allah is angered with those who fall back on their words.
“May Allah’s peace be upon you!” (Bayhaqi, Dalail, II, 524-525)
Including aspects of Islam like belief, worship, moral and social principles, these sermons can effectively be taken as a broad summary of the Religion.
That the Friday Salat was made obligatory even before the completion of Hegira underlines the importance and urgency for Muslims to assemble themselves in a community.
 Qissa, accounts of previous prophets and peoples comprise more than a third of the Quran. For the inherent wisdom in this, refer to Osman Nûri TOPBAŞ, Nebîler Silsilesi, v. 1, p. 11-28, Istanbul 2004.