When talking about his first experience with sin, Paul writes:

For I was alive without the law once: but when the commandment came, sin revived, and I died.
And the commandment, which was ordained to life, I found to be unto death.
For sin, taking occasion by the commandment, deceived me, and by it slew me.

Romans 7:9-11

There once was a time when Paul lived outside of the jurisdiction of God’s Law. When was this? When he was too young to be held accountable to it. The time comes for all of us, however, when we are faced with the temptation to break God’s Law, and in so doing, lose our innocence and purity in the sight of God.

Paul says that by breaking God’s Law he discovered he was spiritually dead. What had happened? Sin had deceived him, he says. Not only so, but it had deceived him and slew him.

Whatever it was that Paul did when committing his first sin, he does not say. Whatever it was, the odds are good that it was something presented by the tempter to be very enticing. Sin always looks its most pleasurable before it is undertaken. Immediately following the sin, the thought of the heart (if soft) turns bitter and remorseful. The sinner says something like “I should have known better.” Indeed we should have, but the temptation of sin is a powerful one.

The only way to resist is to draw nearer and nearer to God (James 4:8) and give no place to the Devil and his lies (Ephesians 4:27).