Why or why not? Please explain with the support of the scripture.
EDIT: Let me rephrase the question to make it clearer. The question is NOT whether a Christian needs to be sinless in order to be saved, but rather, whether a truly born-again Christian with the Holy Spirit living within them would choose to deliberately commit a sin over and over again, with no intention to make effort to eliminate that sin from their life.
For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a terrifying expectation of judgment and the fury of a fire which will consume the adversaries. (Hebrews 10:26-27 NASB)
What shall we say then? Are we to continue in sin so that grace may increase? May it never be! How shall we who died to sin still live in it? (Romans 6:1-2 NASB)
What then? Shall we sin because we are not under law but under grace? May it never be! Do you not know that when you present yourselves to someone as slaves for obedience, you are slaves of the one whom you obey, either of sin resulting in death, or of obedience resulting in righteousness? (Romans 6:15-16 NASB)
No one who abides in Him sins; no one who sins has seen Him or knows Him. Little children, make sure no one deceives you; the one who practices righteousness is righteous, just as He is righteous; the one who practices sin is of the devil; for the devil has sinned from the beginning. The Son of God appeared for this purpose, to destroy the works of the devil. No one who is born of God practices sin, because His seed abides in him; and he cannot sin, because he is born of God. (1 John 3:6-9 NASB)
John 10:27-29 King James Version (KJV)
27 My sheep hear my voice, and I know them, and they follow me:
28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.
29 My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand.
I think it's a nice scare tactic to imply that people are going to hell. I believe that once someone turns to Jesus, they are always on the path towards heaven, even if their life is a total sinful disaster. I inherited a belief in purgatory from my great grandmother, and I believe that people who live sinful lives after turning to Jesus need to be prayed for after they die before they enter heaven. The verse below is in the Catholic Bible, and I think it's considered an optional text for Anglicans. I think someone would have to hate God, Jesus, and make some sort of conscious decision against life in general to go to hell, which is why I don't think many people go there. I would never say at a person's funeral that they had gone to hell, but I would definitely pray for someone to go to heaven after they died, and if they were so evil that they had gone straight to hell, it would be out of my hands. I'll put a passage from Luke about the finality of hell at the very bottom.
2 Maccabees 12:44-45 King James Version (KJV)
44 For if he had not hoped that they that were slain should have risen again, it had been superfluous and vain to pray for the dead. 45 And also in that he perceived that there was great favour laid up for those that died godly, it was an holy and good thought. Whereupon he made a reconciliation for the dead, that they might be delivered from sin.
Luke 16:19-31 King James Version (KJV)
19 There was a certain rich man, which was clothed in purple and fine linen, and fared sumptuously every day:
20 And there was a certain beggar named Lazarus, which was laid at his gate, full of sores,
21 And desiring to be fed with the crumbs which fell from the rich man's table: moreover the dogs came and licked his sores.
22 And it came to pass, that the beggar died, and was carried by the angels into Abraham's bosom: the rich man also died, and was buried;
23 And in hell he lift up his eyes, being in torments, and seeth Abraham afar off, and Lazarus in his bosom.
24 And he cried and said, Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, and cool my tongue; for I am tormented in this flame.
25 But Abraham said, Son, remember that thou in thy lifetime receivedst thy good things, and likewise Lazarus evil things: but now he is comforted, and thou art tormented.
26 And beside all this, between us and you there is a great gulf fixed: so that they which would pass from hence to you cannot; neither can they pass to us, that would come from thence.