We Need the Gospel

As I'm finishing up my sermon prep this morning, I've been reading through Daniel Doriani's book on the Sermon on the Mount. My text for this coming Sunday is Matthew 5:33-37, which deals with oaths and telling the truth. It's a great call for the disciples of Christ to be truth tellers who are trustworthy in all their dealings. However, Doriani suggests that Jesus continues to call us to more difficult tasks as the Sermon goes forth. Indeed, this is true, as we see a great command in Matthew 5:48, "You therefore must be perfect, as your heavenly Father is perfect." It appears that Jesus is setting us up for an impossible task. That is why we need the gospel. The following paragraph is how Doriani addresses the issue:

We need the gospel. It teaches us to ask the one who gives the standard to forgive us for breaking it. We ask the one who kept the standard in perfect righteousness to give us his righteousness and clothe us with it. And the Lord does it. He accepts us as his children and grants us the family resemblance that he requires. For the hardest command is also stated in a way that gives hope. Translated literally, Matthew 5:48 states, "You shall be perfect as your Father in heaven is perfect." We rightly read the words "You shall be perfect" as a command, yet, reading it again, we notice that it hides a promise: you shall be perfect.