In stark contrast to the gospel this marketing slogan sends the wrong message because the one we get for free we have really paid for ourselves.
In this passage we see some very important things about the Law …… it reveals wrong but it cannot make a person who tries to keep it right with God. Why is this? Well the reason is that the Law is spiritual and reveals our innermost failings in a way that makes it impossible to keep. This is because we are ‘fallen in Adam’. In other words we are born with a direction in us which is away from God’s perfect right-ness.
How then can we be right with God? The illustration at the beginning of the chapter tells us. We must ‘die’ to the Law (ie. not try to justify ourselves by our attempts to keep it) and become ‘married’ to Jesus Christ ( justified by trusting in what He has accomplished for us).
There is also another danger which is like having divided loyalties …. trying to be made right by keeping the Law and also coming to Christ for the ‘free’ gift of forgiveness. It cannot be both ways because you are trying to buy one and get one free. It’s not free if you have to pay something to get it. The gospel way, however, is truly free because Jesus paid the price for what we freely receive by faith.