Jesus reveals God in himself, not only in what he said and did, but in who he is. He is the Word of God made flesh. In Jesus we see the glory of God, a glory that does not crush and is not severe. It is a glory which shines through Jesus' humble service and death on a cross for sinners. It is a glory of redemptive and suffering love.
Transgression literally means to step across a line.
God tells us through his word and by our conscience what is right and wrong and what he expects of us. To step across that line is to sin. Disobedience is related to hearing. It literally means imperfect hearing , or careless hearing. In the end it means the unwillingness to hear the voice of God.