Luke's Jesus is serious about sin and the need for people to turn their lives around. But he doesn't seem judgmental. In fact, he makes friends with the "sinners," eating, drinking and, well, partying with them. Plus, he gets a lot of heat for doing so. Think you're safe from the sinner club? You're wrong, says Jesus. People who consider themselves immune to sin are actually part of the club. Better to be self-aware and understand your sinful tendencies.
And how about forgiveness? The Greek word in question here may also be translated as "release," "remission" or "liberation." That means, the concept of "atonement" (i.e., being forgiven for sins by means of Jesus's sacrifice or spilled blood) is not as prominent an idea in Luke as it is in the letters of Paul or even the Gospel of Mark. So how does Luke suggest you liberate yourself from sin? Through baptism, confession in prayer to God, commitment to repentance, and Jesus's own bestowal of forgiveness.