If you subscribed to a doctrine that believers could lose their salvation due to things they either do or don't do, you will take it either from the 4 gospels, or from Hebrews to Revelations, doctrine directed to Israel.
Peter, for example, teach all the Jews that salvation is something they can look forward "in the future", it is never present for them now.
Acts 3:19-20
Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord.
20 And he shall send Jesus Christ, which before was preached unto you:
Acts 3:19 stated that Israel's sins will only be blotted out (past tense) when the times of refreshing shall come. That is not happening now.
If their sins are not blotted out now, how can any of them be saved now?
1 Peter 1 repeats what Peter stated in Acts 3.
3 Blessed be the God and Father of our Lord Jesus Christ, which according to his abundant mercy hath begotten us again unto a lively hope by the resurrection of Jesus Christ from the dead,
4 To an inheritance incorruptible, and undefiled, and that fadeth not away, reserved in heaven for you,
5 Who are kept by the power of God through faith unto salvation ready to be revealed in the last time.
9 Receiving the end of your faith, even the salvation of your souls.
However, if you instead subscribed to OSAS, you will take it from Romans to Philemon, which your detractors here are basically doing.