Actually, I'm secure because God states it in His word and I know that God cannot lie.
John 10:27-30 27 My sheep hear my voice, and I know them, and they follow me. 28 I give them eternal life, and they will never perish, and no one will snatch them out of my hand. 29My Father, who has given them to me, is greater than all, and no one is able to snatch them out of the Fathers hand. 30 I and the Father are one."
2 Corinthians 1:21-22 21And it is God who establishes us with you in Christ, and has anointed us, 22and who has also put his seal on us and given us his Spirit in our hearts as a guarantee.
2 Corinthians 5:4-6 4For while we are still in this tent, we groan, being burdenednot that we would be unclothed, but that we would be further clothed, so that what is mortal may be swallowed up by life. 5He who has prepared us for this very thing is God, who has given us the Spirit as a guarantee. 6So we are always of good courage. We know that while we are at home in the body we are away from the Lord,
Ephesians 1:13-14 13In him you also, when you heard the word of truth, the gospel of your salvation, and believed in him, were sealed with the promised Holy Spirit, 14who is the guarantee of our inheritance until we acquire possession of it, to the praise of his glory.
But, what if you did something really wrong?
James 2:8-11 8If you really fulfill the royal law according to the Scripture, "You shall love your neighbor as yourself," you are doing well. 9But if you show partiality, you are committing sin and are convicted by the law as transgressors. For whoever keeps the whole law but fails in one point has become accountable for all of it. 11For he who said, "Do not commit adultery," also said, "Do not murder." If you do not commit adultery but do murder, you have become a transgressor of the law.
Sin is sin. God hates lying as much as he hates adultery and murder.
Sin is conceived in the heart before it shows in the actions. Jesus said that if you hate your brother it's the same as murdering him; if you lust after a woman, you have already committed adultery with her in your heart.
This business of degree of sin is unScriptural. There is no difference. One sin is all that it takes to condemn someone to hell. If all a person did was commit one sin in their entire life, they'd still need Jesus' blood shed for them for forgiveness of it. And the rest of their perfect life would not be enough to pay that debt and earn, or ensure them a place in heaven.
So what good works is it that you feel God requires of you to complete your salvation and how do you know that you did them all, did enough, or did them adequately, with pure enough motives?
Even if you add your works to the blood of Christ, how do you know it's enough? That ends up putting you back in the same position you were in in the first place, which you wanted to avoid, having to completely trust only in the finished work of Christ on the cross alone.
Sin is sin. God hates lying as much as he hates adultery and murder.
So are you going to hell if you lie? Or are you still saved?