He remained perfect so that he could die to pay for our sins. It was not the Jewish leaders or the Roman soldiers who nailed Jesus to the cross. Our sins nailed Jesus to that cross. When he was nailed to the cross, the Devil was defeated. For Jesus remained perfect and his perfection pays for our sins and blows the lid off of death.
Death holds no more power.
Jesus rose to show his power over death. God raised his Son to show that his payment for our sins covers the entire debt on our Masters' Card. Resurrection tells us we are now truly redeemed children of God. And as children, we await our new home in heaven, which our Lord ascended to heaven to prepare for us. Though his body has departed, Jesus is still with us.