Why does Les wait until he sees a changed life before saying someone has been saved?
A genuine salvation experience produces a changed lifestyle, so a credible confession is confirmed by visible transformation. Until that change appears, it is premature to claim someone has been led to the Lord. Abraham similarly believed God and was declared righteous before his works, showing salvation rests on faith and is followed by evidence.
Les teaches that when there is a genuine salvation, there is going to be a change in lifestyle. He explains that many things follow the salvation experience, but the evidence of salvation is a changed life. That is why he says he will not just run and tell somebody that he led so and so to the Lord until he sees that changed life; then he will gladly share it. Les connects this to Abraham, who was a believer before he ever got out of town and was already declared righteous before he got out of the city wall, because he believed God. Abraham entered in by faith and faith alone based on what God said to him, not by his works.