Praise be to Allah.
The biographers differed concerning the date of the birth of the Prophet (blessings and peace of Allah be upon him), but they are agreed that he died on the twelfth of Rabee‘ al-Awwal, 11 AH. This is the day that is celebrated by the common folk, who call it Mawlid or the birthday of the Prophet (blessings and peace of Allah be upon him).
For more information on this matter, please see the answer to question no. 125690
There is no such thing in Islam as the so-called “Prophet’s birthday”. Neither the Sahaabah nor the Taabi‘een nor the imams or leading scholars of Islam who came after them acknowledged any such day, let alone celebrated it. Rather this festival was introduced by some innovators among the ignorant baatinis (followers of esoteric sects), then the common folk in many regions followed this innovation.
See also the book by Shaykh Saalih al-Fawzaan (may Allah preserve him) criticising this innovation at the following link (in Arabic):
Some of those who love the Sunnah, who have been influenced by what they see of celebrations in their countries, think that they can be safe from falling into innovation by getting together with their families and making special food for this occasion, which they eat together. Some of them gather with their friends and relatives for the same purpose, and others gather with the people to read the biography of the Prophet (blessings and peace of Allah be upon him) or to listen to religious lectures.
Similar to that is your good intention of getting together and instilling a spirit of pride in Islam in western, non-Muslim countries.
But in fact all of these intentions do not make those gatherings of theirs Islamically acceptable; rather they are reprehensible innovations. Indeed, if you are looking for a festival to celebrate, then the two Eids of al-Fitr and al-Adha are the only Eids of the Muslims; if you want any eid apart from that, then in our view Friday is the eid of the week, so gather on that day to offer Jumu‘ah prayer and to instil pride in Islam.
If it is not possible for you to do that, then there are many days in the year, and you can gather on some other occasion, that is not an innovated festival; rather it should be on some permissible occasion, such as a wedding or a gathering for a meal, or an ‘aqeeqah, or to offer congratulations. Any of these may be occasions for doing the things you mention, such as strengthening bonds, getting together and encouraging one another to adhere to Islam.
There follow some fatwas by the scholars concerning the ruling on those who gather with such intentions on that occasion.
1. Imam Abu Hafs Taaj ad-Deen al-Faakihaani (may Allah have mercy on him) said, discussing different types of Mawlids:
(i) When a man organises it at his on expense for his family, friends and children, and in that gathering they do not do any more than eat food; they do not commit any sins. This is what we have described as an abhorrent and reprehensible innovation, because it was not done by any of the early righteous people, who are the fuqaha’ and leading scholars of Islam.
Al-Mawrid fi ‘Aml al-Mawlid, p. 5
2. Ibn al-Haaj al-Maaliki (may Allah have mercy on him) said concerning the ruling on celebrating the Prophet’s birthday without the evils of music, singing and free mixing between men and women:
If it is free of (those evils) and he only makes food and intends it to be for the Mawlid, and he invites others to come and eat, and he avoids everything mentioned above, it is still an innovation just because of the intention, because it is adding something to the religion, and it was not the practice of the earliest generations (the Sahaabah and Taabi‘een), and following the practice of the earliest generations is more appropriate. Rather doing so is a must and nothing should be added that is contrary to their way, because they were the most eager of people to follow the Sunnah of the Messenger of Allah (blessings and peace of Allah be upon him) and to venerate him and his Sunnah, and they were pioneers in doing so. But there is no report that any of them ever intended to celebrate the Prophet’s birthday. We are their followers, so we should be content with what they were content with. It is known that we should follow them in terms of knowledge and practice, as Shaykh Imam Abu Taalib al-Makki (may Allah have mercy on him) said in his book.
3. And he (may Allah have mercy on him) said:
And some of them are cautious to avoid that – i.e., listening to haraam things – and they do the Mawlid by reading al-Bukhaari and so on instead of that. Even though reading hadeeth in and of itself is one of the greatest acts of worship that bring one closer to Allah, and there is great blessing and much good in it, that only applies on condition that it be done in an appropriate, Islamically acceptable manner, not with the intention of the Mawlid. Do you not see that prayer is one of the greatest means of drawing closer to Allah, may He be exalted, but nevertheless if a person does it at a time other than the time prescribed for it, it is blameworthy and contrary to Islam. If this applies to the prayer, then what you think about other deeds?
See also the answer to question no. 117651
To sum up:
It is not permissible for you to gather on that innovatied occasion for the purpose of what you mention of getting together and offering sincere advice. You can achieve these noble aims on some occasions other than this; you have the whole year to organise gatherings on any day. We hope that Allah, may He be exalted, will guide and help you to do good deeds and increase you in guidance.