It seems that there are various ways being "born-again" occurs: flippantly, passively, sincerely and zealously. Which are you? Which am I? They first two are not really ways to salvation!
Ultimately, how serious we are, boils down to our response to grace. First off, to be a Christian no one should believe that it is DESERVED. The entire concept of grace is that we are UNDESERVING, but out of divine love, God can save us because he wants that none should perish as we learn from John 3:16.
In spite of nefarious scrambling of our thoughts, the mind still thinks quickly. As such, any pilgrim on the right road to salvation must quit rationalizing wrong-doing and admit that "all have sinned and come short of the glory of God" (Romans 3:23). Once that admission is forthcoming, and ALL includes YOURSELF, then perhaps you are being serious!
Thinking, I've been good and deserve heaven is the natural man's self-defense mechanism. Within, even those persons knows that they deceive themselves! Just as the drug abuser must admit that an addict has a problem with drugs to be cured, any serious person who wants to live for eternity must admit that there is a sin problem and that "even I have indeed sinned, and by God's standards, deserve to die".
Seriously, how do you feel about sin? Is it pleasurable? Sure it is. Admit that! Is it beneficial? Get serious now: sin is never beneficial. Sure it seems to be, but think rationally now. Sin leads to spiritual death (Genesis 2:17). Adam questioned that very outcome: Eve didn't die and neither will I! Surprise! Both lost their immortality, but because of grace (divine pardon of his underserving children) God saved our forebears. As such they were really born when God covered their sin with fig leaves.
Seriously: sin leads to spiritual death. Do you ever think: I'll ask for forgiveness later after I enjoy the sin? Sure you have! We all have. Grace follows divine principle: for grace to be the sinner must take sin seriously! Remember that and you shall be guarded from sin! By failing the seriousness aspect with "God forgive me for the sin I'm about to do," is taking God for granted because you're not taking him seriously.
Even Adam didn't think: I'll ask for forgiveness later. He just failed to understand that God's standards aren't optional, or maybe questioned God's sincerity. Seriously, when God says things he means them! For instance he gave instructions for carrying the ark of the covenant. It was carried in a different manner and one person (Uzziah) accidentally touched it and died on the spot (2 Samuel 6:7).
God instructed that the ark be carried his way. Uzziah and the others carried it their way. As men always seem to do, they did what's right in their own eyes (Deuteronomy 12:8). When people get serious they change: rather than continuing in their own ways, they want to do what's right in God's way, to do the will of God! What is God's will? Quit'chur sinnin'. Take that seriously because that's how we know that we're saved... by doing God's will.
John 3:36 (ESV) Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him.
Hebrews 10:26 (ESV) For if we go on sinning deliberately after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, 27 but a fearful expectation of judgment, and a fury of fire that will consume the adversaries.There is a test for sincerity... seriously! That test is whether the new person "goes on sinning deliberately". As I often say, "by grace God is not a knit-picker", but he examines each person's heart to see how serious they take his sacrifice. As the second passage says, "after receiving the knowledge of the truth, there no longer remains a sacrifice for sins". In essence, this verse points out that Jesus was the sacrifice, and when one is enlightened by truth, continuing in sin would cause Jesus to be vicariously hung on the cross again! In short, you must take his only sacrifice seriously!
Even though God's grace is sufficient, by continuing a life if sin are you serious about being a Christian? By becoming a new creation, the implication is that the old person has died! Seriously, has that old person truly died? We are assured of our salvation when we know that indeed we are new persons. By obeying God is a measure of our sincerity. Seriously!
Our works are not the measure. Doing good things are not the metric. The measure of our sincerity, is our own DESIRE to please God. What pleases God? Our obedience. That's how we demonstrate to God that we love him (John 14:15). We may not get emotional when we think on God's sacrifice of his son, but if we're serious, we love him by obedience. Thinking: grace will cover my pleasure is flippant and disregards God's will. We must get serious about obedience because obedience comes forth from love.
In our hearts we all know if we truly are new creations. However, we must soberly examine our desire to do God's will. We must take the propitiation of Jesus' blood and life seriously, not merely believing that he died for us, but loving him for it! Jesus' sacrifice must be internalized. We must think: he died in MY place, and appreciate him for it. How must we show our gratitude? By being serious!