Ah! You have to give me a little time. I needed to help my daughter do some research for a car she want to buy - my internet rambling had to wait - and even now I only have a few minutes: After I am done - you will likely have more I need to answer - and I will not be back till tomorrow!
You will have to be patient!
So you jumped in and strung two verses together before I could answer the question you asked - that is OK - because I like to have a lot of fun stringing verses together too . . .
First one:
I Cor. 7:
18 Is any man called being circumcised? let him not become uncircumcised. Is any called in uncircumcision? let him not be circumcised.
19 Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God.
20 Let every man abide in the same calling wherein he was called.
So circumcision or uncircumcision is a "calling" and if the "gifts and calling" of God are irrevocable (Rom. 11:29 )then we will be circumcised or uncircumcised in heaven as we are here on Earth.
Second one:
And prophecy is a gift - and since the "gifts and calling of God" are irrevocable then that means if you have the gift of prophecy now you will have it for all eternity. !!! ??? but this is not what I Corinthians 13 says about prophecy: Verse 8 says: "But where there are prophecies, they will cease;"
And if you want more crazy ones that these, they sure are out there: all the cult groups get their doctrine by stringing verses together.
If you want to convince me of OSAS, you have got to show me a verse in its context that clearly says that once a person is saved they will always be saved.