Hi and want a little space , because we are seeing thing in different light !!You have not shown WHERE Peter preached the MYSTERY or given a verse where Peter said here is what the MYSTERY IS and I has present it to you and you have Ignored it !!
In Acts 15:11 we read , But we beleive THOUGH the Grace of the Lord Jesus Christ to be saved as they also !!
#1 , The first verb says , WE BELIEVE / PISTEUO kis in the Present tense , of the Law of Moses since the quote in verse one it all about Circumcision !!
#2 , It is in the Active Voice which means that the subject as present by Peter , Circumcsion !!
#3 , The Indicative Mood means Acts 15:11 is a FACT as written !!
#4 , So we see that Peter was still teaching the Law of Moses !!
#5, And we , the Jews , Peter says SHALL BE SAVED , as the Gentiles are saved by Grace !!
#6 So we see that Peter is not teach Grace BUT said that Jews will also be saved as GENTILES are saved !!
#7 By the way the verb WE SHALL BE SAVED is in the Aorist Tense and means from then on Jew and Gentiles will be saved by Grace as ACTS 15:8and 9 !!
And I see why you do not understand as Acts 2 people ALWAYS denigrate Paul and never believe what Paul has written !!
Here's the mystery.
1 Peter 4:12
Beloved, think it not strange concerning the fiery trial which is to try you, as though some strange thing happened unto you: