What did the previous prophets said about their religion?

Well… no one knows about what the previous prophets said about their religion. The only clue about this is by reading the holybook, that is the Holy Quran.

QS. Al-Baqarah 131

When his Lord said to him, “Submit! (=Aslim!)”, he said “I have submitted [in Islam] (=aslama) to the Lord of the worlds (universe).” [QS. Al-Baqarah 131]

QS. Al-Baqarah 132

And Abraham instructed his sons [to do the same] and [so did] Jacob, [saying], “O my sons, indeed Allah has chosen for you this religion, so do not die except while you are Muslims.” [QS. Al-Baqarah 132]

QS. Al Baqarah 133

Or were you witnesses when death approached Jacob, when he said to his sons, “What will you worship after me?” They said, “We will worship your God and the God of your fathers, Abraham and Ishmael and Isaac – one God. And we are Muslims [in submission] to Him.” [QS. Al Baqarah 133]

 

QS. Al-Baqarah 136

Say, [O believers], “We have believed in Allah and what has been revealed to us and what has been revealed to Abraham and Ishmael and Isaac and Jacob and the Descendants and what was given to Moses and Jesus and what was given to the prophets from their Lord. We make no distinction between any of them, and we are Muslims [in submission] to Him.” [QS. Al-Baqarah 136]

 

What is Islam?

The word “Islam” came from the following words:
aslama : submitted, surrendered.
yuslimu : to submit, to surrender.
aslim : submit!, surrender! (imperative).
muslim : peope who are submit, surrender.
Islam : submission, surrender.
Another word came from the same root is salaam, which means peace.
Thus, Islam means to surrender to God in all aspect of life to achieve peace in this world and afterlife.

What did the previous prophets said about their religion? Go to this article.