I grew up in a Free Methodist church, so heard about sanctification. I believed that salvation was choosing to be in relationship with God, and so entering into eternal life both now and after death, on the basis of that choice. Then, a saved person would be naturally drawn to be wholly given to God in all areas, which is sanctification. This would be starting at the salvation point, and was just the start of a life-long process of allowing the Holy Spirit to transform us. I figured all Christians would be cooperating with the transformational work the Holy Spirit does in our lives, whether they call it sanctification or have never heard of the term, just because His Spirit in us draws us into further relationship.
However, I was also taught that there will come a point where a person being transformed makes an absolute decision to surrender their will entirely to God, and that was the complete sanctification point. I do not consider a person perfect at that point. I think the doctrine of complete/entire sanctification would say it is possible, in cooperation with the Holy Spirit, to be free of willful and deliberate sin on earth. I believe Wesley taught that, and imagine it was what the pastor today was saying in terms of being sinless via sanctification. I do not believe Wesley or any denomination taught that a person wasn't saved until that point, though. And when it is taught in other denominational contexts, I'm thinking of Victory through Surrender by E. Stanley Jones, the concepts of surrendering to His Lordship I heard in a college group led by a Baptist minister, a call to dedicate all of the self to Christ I heard in a non-denominational church etc., it was still the same thing my upbringing called entire or complete sanctification.
He preached that sanctification is an act that happens when a person is convicted by God, after having asked for salvation, to become sinless, and that without sanctification, you cannot get into heaven.
If your understanding is what he was trying to communicate, I abhor that vision of God. I think I would have found it scary as a child! I wouldn't want my kids to hear what yours did today. As an adult I find it absolutely incompatible with what I see in Christ, who is the exact representation of God. So ick. Of course, I heard a Nazarene pastor say from the pulpit that if he had argument with his wife, walked out in selfish anger, and was hit by a car he would go to hell. From that perspective, it doesn't surprise me that someone might preach the above! At the time, I termed it eternal insecurity. The above fits well with that line of thinking! I don't believe it's biblical, but maybe he was trying to say something different than what was communicated.