Why can a person not say "La ilaha illallah" to become Muslim? Why "Muhammadur RasulAllah"?
Because, accepting the Prophet :saws: wholeheartedly and obeying him :saws: unconditionally, is a condition for our faith. Without this, we cannot be Muslim. We must take what he :saws: gave us, leave what he :saws: forbade us, and follow his :saws: beautiful example, and after him, that of his rightly guided companions, and those who learnt from them. We should love him :saws: as much as we can, in the way he :saws: taught us we should, and not any ways invented after him :saws:. Nobody loved him :saws: more than his companions (may Allah be pleased with them), and we should pray and try that we may follow their example and love him the same way they did, which he approved of. We should ask Allah to save us from overstepping the mark, as the Prophet :saws: told us to avoid. and truly, the way to love him is beautifully spelled out in the Qur'an, in Allah's own words, commanded by Allah to the Prophet :saws; to say:
Say [O Muhammad, saws]: If you love Allah, then follow me, Allah will love you and forgive you your sins, and Allah is Forgiving, Merciful. (Qur'an, Surah Aale Imraan, surah 3, ayah 51)
Prophet :saws: narrated: “Allah said: When Adam made the mistake, he asked: 'O Allah! I ask you for the sake of Muhammad to forgive me.' Allah said: 'O Adam! How do you recognize Muhammad when I have not yet created him?' Adam said: 'O Allah! When you created me and blew into me the spirit, I lifted my head and saw written on the `Arsh ‘La ilaaha illallah Muhammadur rasoolullah’.' So, I got to know that you would only join your name with him who is most beloved to you. Allah said: 'O Adam! You have spoken the truth. Indeed Muhammad is more beloved to me than anything and when you asked me for his sake, I pardoned you. If Muhammad was not in existence, I would not have created you'.”
Reports that say the Earth was created for the Prophet :saws: are either extremely weak or fabricated, and not sound. See:
https://www.islamweb.net/newislamwe...ted-for-muhammad-sallallaahu-alayhi-wa-sallam
http://islamqa.info/en/23290
Jabir ibn `Abd Allah said to the Prophet :saws:: "O Messenger of Allah, may my father and mother be sacrificed for you, tell me of the first thing Allah created before all things." He said: "O Jabir, the first thing Allah created was the light of your Prophet from His light, and that light remained in the midst of His Power for as long as He wished, and there was not, at that time, a Tablet or a Pen or a Paradise or a Fire or an angel or a heaven or an earth. And when Allah wished to create creation, he divided that Light into four parts and from the first made the Pen, from the second the Tablet, from the third the Throne, [and from the fourth everything else]."
The above "hadeeth" is a fabrication falsely atrributted to the Prophet :saws: and to Jaabir (may Allah be pleased with him)
"Moreover it is proven that the angels are the ones who were created from light, not any of the sons of Adam. The Prophet (peace and blessings of Allaah be upon him) said: “The angels were created from light, and Iblees was created from smokeless fire, and Adam (peace be upon him) was created from what has been described to you.” Narrated by Muslim, 2996. "
"This indicates that the well known hadeeth (report) that is in circulation among people – “The first thing that Allaah created was the light of your Prophet, O Jaabir” – is false, and so are other similar ahaadeeth (narrations) which say that the Prophet (peace and blessings of Allaah be upon him) was created from light. This hadeeth clearly indicates that the angels are the only ones who are created from light, not Adam and his sons, so pay heed and do not be negligent."
http://islamqa.info/en/75395
"It is a fabricated Hadeeth"
http://www.islamweb.net/emainpage/index.php?page=showfatwa&Option=FatwaId&Id=83805
Prophet Yahya alayhis salaam was saying about his own birthday which Allah talks about him saying the Holy Qur'an:
وَسَلَامٌ عَلَيْهِ يَوْمَ وُلِدَ وَيَوْمَ يَمُوتُ وَيَوْمَ يُبْعَثُ حَيًّا
wa salaamun `alayhi yawma wulida wayawma yamootu wayawma yub`athu haayyaa
"And may peace and blessings be upon the day he was born..." (Surah Maryam 19:15)
So, Prophet Yahya alayhis salaam can say that about his birth date, yet Muslims cannot say that for the most honorable creation Prophet Muhammad :saws:?
The day of ones birth, is entirely different from making an annual celebration called birthday, be it ours, Jesus alayhissalaam, or Prophet Muhammad's :saws:.
Jazaakumullahu khayr.