Suppose this year for your spouse’s birthday you want to do something really special. So you decide to make a birthday cake unlike anything your spouse has ever seen. You do the research. You bake some ‘practice cakes’. And then finally after weeks of preparation, the cake is ready for the big occasion.
On the day of the birthday party I come around to your house early to help set everything up. I see the cake and think that it looks amazing. It is by far the most impressive cake I’ve ever seen. In fact, I’m so overwhelmed with how good it is, that I take it upon myself to add my own finishing touches.
I grab some whipped cream and pour it all over the cake. I then carefully place marshmallows all over the top. Then I finish it off by pouring out three large packets of m&m’s onto the cake.
Now of course this whole thing is a disaster. Firstly, it is incredibly rude for me to look at the amazing cake that you’ve made and feel like I’ve got to add to it. Secondly, the cake now looks terrible. In my attempt to add to what you have done, I have actually destroyed what you have done.
The same thing happens when we try to add to what Jesus has done on our behalf.
A lot of people believe that Jesus died on the cross to pay for our sin, but they don’t believe that His work is complete. They feel that they need to add to what Jesus did to make us righteous before a Holy God. So they end up trusting in a combination of Jesus’ work plus their own works to get them to heaven.
And again, this whole thing is a disaster. In the same way that it’s incredibly offensive for me to look at your amazing birthday cake and feel like I’ve got to somehow add to it, it’s also incredibly offensive for us to look at Jesus’ perfect sacrifice and feel like we’ve got to somehow add to it. And just as my attempt to add to your perfect cake actually destroyed it, any attempt we make to add to Jesus’ perfect sacrifice actually destroys His work on our behalf.
There is nothing wrong with doing good works. Christians are called to do good works in response to what Jesus has done for them. But it’s an entirely different thing again to look at the perfect Son of God and His work on the cross and conclude that it’s not enough to save us.
Jesus said: “It it finished”. We need to rest in that.