Scripture doesn’t agree with OSAS as stated below.
“2. Can a true Christian lose his salvation? The Bible argues he cannot: once saved, always saved.”
“no one can snatch them out of my Father’s hand”
Absolutely no power can take a believer from God’s hand, but you can renounce you salvation. With that being said your salvation wasn’t taken you gave it away. In more human terms your citizenship cannot be taken from you, but you sure can renounce it.
John 8:31 King James Version (KJV)
31 Then said Jesus to those Jews which believed on him, If ye CONTINUE in my word, then are ye my disciples indeed;
2 John 9 King James Version (KJV)
9 Whosoever transgresseth, and ABIDETH not in the doctrine of Christ, hath not God. He that ABIDETH in the doctrine of Christ, he hath both the Father and the Son.
1 John 2:24 King James Version (KJV)
24 Let that therefore abide in you, which ye have heard from the beginning. If that which ye have heard from the beginning SHALL remain in you, ye also shall CONTINUE in the Son, and in the Father.
2. It’s past-tense: “he has crossed”, he “has eternal life,” which by definition is eternal and cannot be lost.
I was saved past tense all that means is yesterday for tomorrow I could start my old life again and trust me I wouldn’t not be in Jesus nor him in me. Again it’s eternal if you continue in the repentant life that Jesus has called us to live.
3. In Christ = no condemnation
Absolutely true if you continue “IN CHRIST” as stated above.
The New Covenant requires two parties both have to uphold there part to stay in force. God will always uphold his part, but we must continue in our part also.
If you couldn’t lose you salvation then Satan would NOT tempt believers we would be a lost cause OSAS. Please don’t tell me that we would lose reward because a ghetto seat in Heaven will be better than the best seat in Hell!
Jesus was tempted also and by his own free will he resisted and by his own free will he went to the Cross. I think if you really study this Scripture you will notice that Jesus had free will to chose and if he had choice why would you think we don’t?
John 10:18 King James Version (KJV)
18 No man taketh it from me, but I lay it down of myself. I have power to lay it down, and I have power to take it again. This commandment have I received of my Father.
Lucifer was saved and lost his Salvation, so how did that work?
Bottom line: You can lose your salvation if you surrender it, but it cannot be taken from you by any power or force.
In my understanding of the Scriptures, including every one you cited, if one were to "renounce" his salvation, it would only demonstrate that he had never actually had it. In my view, God would intervene before a true believer ever reached that point of renunciation, either by encouraging his (eventual, sooner or later) continuation in the faith, or if necessary by simply ending his sojourn in this life and welcoming him to His presence.