Leslie,
Thank you for your question and for your sincere desire to simply know why Islaam teaches this.
As my brother r.gonzales wrote, Islaam comes from the arabic word “aslama”, which means “to submit”. And the word Islaam itself means submission, as it is merely a derivation of this word.
Yes, Muslims do believe that “Islaam” was the religion of all of the Prophets, as Allaah says in the Quraan:
“Abraham was neither a Jew nor a Christian; but he was an upright Muslim.”
Now, please do know Leslie that the labeling of the prophets as Muslim does not mean that we believe they followed all the religious teachings as taught in the religion of Islaam today. It does not mean that Abraham was commanded to pray five times a day, or commanded to fast the month of Ramadan, or commanded to make hajj. This is definitely not what Allaah means in this verse, and it is surely not what Muslims are implying, although it is often incorrectly inferred.
Rather, Allaah called prophet Abraham a Muslim because he truly was the best of those (in his time) who submitted to his Lord…so much so, that he was willing to sacrifice his son.
And because there is often debates between Christians and Muslims, and Christians and Jews, and even between Christians themselves, regarding the trinity, deity of Jesus, peace be upon him, and other things. Because of this, in Islaam, Allaah makes things very simple. Allaah in the Quraan commands Muslims: “Follow the religion of Abraham, for he was an upright Muslim.”
As discussed in another post, what was the religion of Abraham? He was not a Jew, as the Jews are named after the tribe of Judah, which was a great Grandson of Abraham, peace be upon him. Abraham was not a Christian, as this would imply that he was a follow of Christ. Abraham was not a following of Budda or Confusius. And Abraham was also not a muslim, IN THE SENSE of following prophet Muhammad, peace be upon him. Rather, Abraham’s religion was one of simply beleiving in the one true God, the Creator of all, and to worship Him alone without partners, and to submit his will to the will of his Lord. And as such, he was a “muslim” (one who submits) in the true sense of the word.
And for this same reason, we believe that all of the prophets were Muslims, as all of them submitted thier will to the Creator, to the God of all, and each of them came with the same message, as Allaah says in the Quraan:
"And assuredly, we sent to every nation a Messenger saying, ‘Worship God (alone) and avoid false dieties.’ "
Hopefully this helps to answer your question Leslie.
Please feel free to ask any questions, as this only helps to gain a mutual understanding.
