Q: can a man continue to keep sinning after He has believed? (salvation?)
A: YES! 1 John 1
FAITH and WORKS go hand-in-hand! James 2:22
Romans 8 (NASB)....Deliverance from Bondage
1 Therefore there is now no condemnation for those who are IN Christ Jesus.
2 For the law of the Spirit of life IN Christ Jesus has set you free from the law of sin and of death.
37 But in all these things we overwhelmingly conquer through Him who loved us.
38 For I am convinced that
neither death, nor life, nor angels, nor principalities, nor things present, nor things to come, nor powers,
39 nor height, nor depth, nor any other created thing,
will be able to separate us from the love of God, which is in Christ Jesus our Lord.
John 10 (NASB)...ETERNAL SECURITY of BELIEVERS' SALVATION
27 My (saved) sheep hear My voice, and I know them, and they follow Me;
28 and I GIVE (UNEARNED) eternal (SPIRITUAL) life to them, and they will never perish; (ETERNAL SEPARATION FROM GOD)
and no one will snatch them out of My hand.
29 My Father, who has given them (BELIEVERS) to Me, is greater than all;
and no one is able to snatch them out of the Father’s hand.
30 I and the Father are one.” (IN spiritual essence and nature)