There is no mixing of the law with grace. The law relies on what we do for God; grace relies on what God has done for us. Jesus used two parables to describe what happens when we try to mix them. One dealt with a wineskin in Matthew 9:17 (also Mark 2:22, Luke 5:37-38). New wine was put into a wineskin to ferment, the skin stretched to accommodate both the wine and the expanding gas. However, that skin could only stretch a limited amount before breaking, so repeating the process by putting new wine in that same wineskin which had already been stretched would be destructive to both the skin and the wine –the skin would break and the wine would be lost!
He frequently used wine to symbolize His own blood –that is His life. So the analogy of the wineskin is so appropriate to show us about our relationship with Him. We are the wineskins and the law shows us our need for Him. After recognizing that need, we accepted His offer of new life and then He stretched us with Spirit’s influence as that life matures. Having filled and stretched us, we have no need for the law to show us that we need Jesus. We have Him; salvation has already been accomplished –“It is finished!”
The second parable comes from Matthew 9:16 (also Mark 2:21, Luke 5:36) and is about a new piece of cloth used as a patch on an old garment. This one also describes our relationship with God. The garment, that’s us again, starts out made from new cloth. As dirt became apparent on it and the need for washing became clear (the law pointed out our uncleanliness). We accepted Jesus as savior and He washed, sanctified and justified us (1 Corinthians 6:11). When we use the law to show our faults, then we think we need new patches (rededicating, rewashing, recommitting) every time that we sin. That one washing was sufficient because it was done by the Lord Jesus Christ. Continuing to use the law in a Christian’s life is destructive –that patch will come loose and tear us apart.
The law is not based on faith. The law and faith are contrary to one another. Adding even the slightest bit of the law to a Christian’s faith is like adding a bit of leaven to a batch of dough. It works its way through the whole thing ruining it all. Trying to keep the simplest part of the law destroys a life of faith! Serving God –bearing fruit for Him– can only be accomplished when a Christian lives by faith