Is "once saved, always saved" biblical? Can a Christian lose salvation?
Yes, it is biblical, and no, a true believer cannot be lost. The moment a person believes he is sealed with the Holy Spirit "unto the day of redemption" (Eph 1:13, 4:30), and Jesus says of His own, "they shall never perish, neither shall any man pluck them out of my hand" (John 10:28). The security rests on Christ's grip, not the believer's.
What the text states
The proof runs on who does the keeping. "I give unto them eternal life; and they shall never perish... My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand" (John 10:28-29). Two hands, and the sheep is held in both. The seal is God's own Spirit (Eph 4:30), the earnest, the down payment guaranteeing the rest (Eph 1:14). A gift that can be lost by the one who received it was never a guarantee; Paul calls it exactly a guarantee.
Arminianism holds that a genuine believer can forfeit salvation through persistent unbelief or apostasy, pointing to the warning passages (Heb 6, Heb 10) and branches "cut off" (Rom 11). We read the warnings as real and addressed to real hearers, but as calls that God uses to keep His own, not evidence the sealed can be unsealed. Where a professor finally falls away, Scripture's verdict is 1 John 2:19, "they went out from us, but they were not of us," not that a son of God was lost.
Go deeper
Checked 2026-09-29 by Darren. 59 Scripture citations verified against the KJV rows. 59 quoted fragments table-passed against the verses table. One correction: once-saved-always-saved cited “unto the day of redemption” to Eph 1:13; the phrase is Eph 4:30, corrected to (Eph 1:13, 4:30) to match the convention used in eternal-security-vs-perseverance. 18 exhibit links checked, all resolve.
This answer is the short form. The argument is made at length in The Road Not Taken.