Can a child of God lose his salvation through sin or disobedience?
No, he can not. This question is really about the effectiveness of the sacrifice of Jesus Christ. I am convinced that once one properly understands the Biblical teaching on how a man is saved, he will know that he is secure in Christ. Some Bible facts that show this are:
1) Salvation is not of our works, but by the finished work of Christ. It could only be lost if it were conditioned on our works.
“For by grace are you saved through faith, and that (being saved), is not of yourselves, it is the gift of God; not of works, lest any man should boast.” (Ephesians 2:8-9)
2) Salvation is an everlasting relationship entered by faith and kept by the power of God.
“And I give unto them eternal life and they shall never perish, neither shall any pluck them out of my hand.”
3) Salvation is of the Lord. His promise is sealed with the Holy Spirit and His covenant cannot be broken.
“In Whom (Christ) also when you believed, you were sealed with that Holy Spirit of promise, Who is the earnest (the down payment or guarantee) of our inheritance.”
(See also: Titus 1:2; Romans 11:29 - note: “without repentance” means irrevocable)
God, Who has begun a good work in us, will finish what He has started (Philippians 1:6). This shows the fallacy of the argument that eternal security would lead to sinful living. God now deals with us as sons. As a faithful Father, He works in our lives to see that we grow up righteously, lovingly correcting us when we stray (Hebrews 12:5-11).
by David Cannon