Islam is the religion of all Prophets, peace be upon them

 I take refuge with Allaah from the accursed devil. 
بِسْمِ اللَّهِ الرَّحْمَـنِ الرَّحِيمِ
  Bismillah-ir-Rahman-ir-Raheem: In the name of Allah, the Compassionate, the Merciful. 
  Welcome to my blog and praise the Magnificent Lord as you enter: Allahu Akbar: Allah is the Greatest .
  May the Peace and Blessing of Allah Azza wa Jal, our Lord Glorified and Praised be He, be upon our beloved  Prophet, his Family, and Companions.
Islam is the religion of all Prophets, peace be upon them.
قُلْ إِنَّنِى هَدَانِى رَبِّى إِلَى صِرَطٍ مُّسْتَقِيمٍ دِينًا قِيَمًا مِّلَّةَ إِبْرَاهِيمَ حَنِيفًا وَمَا كَانَ مِنَ الْمُشْرِكِينَ
(161. Say: “Truly, my Lord has guided me to a straight path, a right religion, the religion of Ibrahim, Hanifan (monotheism) and he was not of the Mushrikin.”)
 قُلْ إِنَّ صَلاَتِى وَنُسُكِى وَمَحْيَاىَ وَمَمَاتِى للَّهِ رَبِّ الْعَـلَمِينَ
(162. Say: “Verily, my Salah, my sacrifice, my living, and my dying are for Allah, the Lord of all that exists.”)
لاَ شَرِيكَ لَهُ وَبِذَلِكَ أُمِرْتُ وَأَنَاْ أَوَّلُ الْمُسْلِمِينَ
(163. “He has no partner. And of this I have been commanded, and I am the first of the Muslims.”)
Surah 6 Al Anaam Verse 161-163
Tafsir Ibn Kathir
 Allah commands His Prophet , the chief of the Messengers, to convey the news of being guided to Allah’s straight path. This path is neither wicked, nor deviant,
(a right religion…) that is, established on firm grounds,
(The religion of Ibrahim, Hanifan and he was not of the Mushrikin.) Allah said in similar Ayat,
(And who turns away from the religion of Ibrahim except him who deludes himself) [2:130], and,
(And strive hard in Allah’s cause as you ought to strive. He has chosen you, and has not laid upon you in religion any hardship: it is the religion of your father Ibrahim.) [22:78], and,
(Verily, Ibrahim was an Ummah (or a nation), obedient to Allah, a Hanif, and he was not one of the Mushrikin. (He was) thankful for His (Allah’s) favors. He (Allah) chose him (as an intimate friend) and guided him to a straight path. And We gave him good in this world, and in the Hereafter he shall be of the righteous. Then, We have sent the revelation to you (saying): “Follow the religion of Ibrahim, (he was a) Hanif, and he was not of the Mushrikin”) [16:120-123]. Ordering the Prophet to follow the religion of Ibrahim, the Hanifiyyah, does not mean that Prophet Ibrahim reached more perfection in it than our Prophet . Rather, our Prophet perfectly established the religion and it was completed for him; and none before him reached this level of perfection. This is why he is the Final Prophet, the chief of all the Children of Adam who holds the station of praise and glory, the honor of intercession on the Day of Resurrection. All creation (on that Day) will seek him, even Ibrahim the friend of Allah, peace be upon him [to request the beginning of Judgement]. Imam Ahmad recorded that Ibn `Abbas said, “The Messenger of Allah was asked, `Which religion is the best with Allah, the Exalted’ He said,
(Al-Hanifiyyah As-Samhah (the easy monotheism))”
Allah said next,
(Say: “Verily, my Salah, my sacrifice, my living, and my dying are for Allah, the Lord of the all that exists.”) Allah commands the Prophet to inform the idolators who worship other than Allah and sacrifice to something other than Him, that he opposes them in all this, for his prayer is for Allah, and his rituals are in His Name alone, without partners. Allah said in a similar statement,
(Therefore turn in prayer to your Lord and sacrifice.) [108:2], meaning, make your prayer and sacrifice for Allah alone. As for the idolators, they used to worship the idols and sacrifice to them, so Allah commanded the Prophet to defy them and contradict their practices. Allah, the Exalted, commanded him to dedicate his intention and heart to being sincere for Him alone. Mujahid commented,
(Verily, my prayer and my Nusuk…) refers to sacrificing during Hajj and `Umrah.
The Ayah,
(and I am the first of the Muslims.) means, from this Ummah, according to Qatadah. This is a sound meaning, because all Prophets before our Prophet were calling to Islam, which commands worshipping Allah alone without partners. Allah said in another Ayah,
(And We did not send any Messenger before you but We revealed to him (saying): “None has the right to be worshipped but I, so worship Me.”) [21:25] Allah informed us that Nuh said to his people,
(But if you turn away, then no reward have I asked of you, my reward is only from Allah, and I have been commanded to be of the Muslims.) [10:72] Allah said,
(And who turns away from the religion of Ibrahim except him who deludes himself Truly, We chose him in this world and verily, in the Hereafter he will be among the righteous. When his Lord said to him, “Submit (i.e. be a Muslim)!” He said, “I have submitted myself (as a Muslim) to the Lord of the all that exists.” And this was enjoined by Ibrahim upon his sons and by Ya`qub (saying), “O my sons! Allah has chosen for you the (true) religion, then die not except as Muslims.”)[2:130-132]. Yusuf, peace be upon him, said,
(My Lord! You have indeed bestowed on me of the sovereignty, and taught me something of the interpretation of dreams — the (Only) Creator of the heavens and the earth! You are my Wali (Protector) in this world and in the Hereafter. Cause me to die as a Muslim, and join me with the righteous.) [12:101] Musa said,
(And Musa said: “O my people! If you have believed in Allah, then put your trust in Him if you are Muslims.” They said: “In Allah we put our trust. Our Lord! Make us not a trial for the folk who are wrongdoers. And save us by your mercy from the disbelieving folk”) [10:84-86] Allah said,
(Verily, We did send down the Tawrah, therein was guidance and light, by which the Prophets, who submitted themselves to Allah’s will, judged for the Jews. And the rabbis and the priests [did also].) [5:44], and,
(And when I (Allah) inspired Al-Hawariyyun (the disciples) [of `Isa] to believe in Me and My Messenger, they said: “We believe. And bear witness that we are Muslims.”) [5:111] Therefore, Allah states that He sent all His Messengers with the religion of Islam, although their respective laws differed from each other, and some of them abrogated others. Later on, the Law sent with Muhammad abrogated all previous laws and nothing will ever abrogate it, forever. Certainly, Muhammad’s Law will always be apparent and its flags raised high, until the Day of Resurrection. The Prophet said,
(We, the Prophets, are half brothers, but our religion is one.) Half brothers, mentioned in the Hadith, refers to the brothers to one father, but different mothers. Therefore, the religion, representing the one father, is one; worshipping Allah alone without partners, even though the laws which are like the different mothers in this parable, are different. Allah the Most High knows best. Imam Ahmad recorded that `Ali said that when the Messenger of Allah used to start the prayer with Takbir [saying, "Allahu Akbar'' (Allah is the Great)] he would then supplicate,
(I have directed my face towards He Who has created the heavens and earth, Hanifan and I am not among the Mushrikin. Certainly, my prayer, sacrifice, living and dying are all for Allah, Lord of the worlds.)
(O Allah! You are the King, there is no deity worthy of worship except You. You are my Lord and I am Your servant. I have committed wrong against myself and admitted to my error, so forgive me all my sins. Verily, You, only You forgive the sins. (O Allah!) Direct me to the best conduct, for none except You directs to the best conduct. Divert me from the worst conduct, for only You divert from the worst conduct. Glorified and Exalted You are. I seek Your forgiveness and repent to You.) This Hadith, which was also recorded by Muslim in the Sahih, continues and mentions the Prophet’s supplication in his bowing, prostrating and final sitting positions.