To make it brief. The New Testament is the fulfillment of the Old Testament. It's not that the old doesn't exist or isn't practical in some instances. It's that the New completes the Promise that God made to Adam and Eve in the garden. Because man sinned, all of humanity is cursed. God spends the whole Old Testament raising up the nation of Israel so that he might fulfill his promise to defeat sin with the sacrifice and death of Jesus. A lot of the laws and customs of the Old Testament...like sacrificing bulls and such....are now obsolete because the death and resurrection of Jesus fulfills the requirements of the old law. Belief and faith in him allows believers to live unto Christ and be made perfect and new in his eyes. Whereas before, all the laws, and sacrifice just covered up our sin. The New Testament is the good news that allows us to been seen as sons of God and be accepted into his Kingdom. And we aren't perfect...by any means..I guarantee I'm the biggest sinner I know. But we are being made into the perfect image of Christ one day at a time. Seriously man I could talk for ages about this. If you ever wanna game together if you got more questions I'm totally up for it.