Can a believer commit suicide? I think a born again believer wouldn’t take their own life because of the indwelling of the Holy Spirit.
But what about Samson, who selfishly brought down the temple on the Philistines and also killing himself?
There are several clear passages in Scripture that describe the permanent nature of our salvation decision, and several others that explain that once we’re saved, it’s the Lord’s job to make sure we wind up in heaven with Him. Hebrews 10:12-14 is a good example.
But there are no passages implying that the Holy Spirit takes control over our lives. Jesus called Him “the Counselor” and that’s just what He is. Every time you sin you’re overriding the Holy Spirit’s counsel. And when you feel guilty afterward you’re experiencing His conviction for having done so. Confession is the antidote He gave us for that guilt.
He can’t prevent you from doing anything that you’re determined to do because He won’t deprive you of your power of choice. So yes, believers continue to sin and even commit suicide.
As for Samson, his was not simply a selfish act of revenge as a surface reading implies, but came out of his prayer that God would give him one final chance to do what he had been called to do, and that’s to begin Israel’s deliverance from the Philistines (Judges 13:5). The fact that God answered his prayer for supernatural strength again indicates that Samson had repented, reinstated his Nazarite vow (symbolized by letting his hair grow again in v.22) and earned the Lord’s favor again during his time of captivity. Otherwise, the Lord would not have restored his strength.