Matthew chapter three tells of a time when John the Baptist was "preaching in the wilderness of Judea, saying, 'Repent, for the kingdom of heaven is at hand.'" That word "repent" is the Greek word "metanoeo", which means to think differently afterwards, according to Strong's Concordance. John the Baptist was voicing the Lord's call for us to acknowledge our sin. We have to think differently about our sin, in essence, calling it what it is.
In verse seven, some Pharisees and Sadducees came to John for baptism. They didn't receive the welcome that they, or we for that matter, might expect. Now, don't misunderstand John. He was right to turn them away. John knew that they had not repented. In their self-righteousness, they had come to participate in baptism illegitimately. Maybe they had come to take part in a ritual that they thought might bring them into God's good graces. Or, maybe they had taken notice of all of the people being baptized by John and they felt threatened by what they perceived to be his influence. Maybe they came to co-opt what the Lord was doing, in an attempt to "stay relevant". (That should sound familiar, as many churches and ministers today have sold their souls in an attempt to stay "relevant", as if any part of God's Word were irrelevant.) Whatever their reason was for coming, they didn't get far. In verses 7-8, John called them snakes and told them that if they believed that they were righteous then they ought to act like it.
Gentlemen, we have to heed the Word that the Lord spoke through His servant John the Baptist, and "bring forth fruit in keeping with repentance". We cannot fall into the trap that ensnares so many around us. We have to stop thinking about what we can get by with, and start thinking about what the One who saved us wants from us. If we have come to "think differently" about our sin, then we need to walk instead in obedience to God, according to His Holy Spirit. Our pride and our sin are nothing to smirk about, and are certainly nothing to try to justify.
"What benefit were you then deriving from the things of which you are now ashamed? For the outcome of those things is death. But now having been freed from sin and enslaved to God, you derive your benefit, resulting in sanctification, and the outcome, eternal life. For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord."-Romans 6:21-23