Are our hearts still deceitfully wicked after we are born again?
First of all, we understand immediately why the unregenerate heart is desperately wicked and beyond our understanding. That is how we can understand and interpret the headlines around us. Frankly, that's how we can understand the mirror in front of us. It is the knowledge of depravity, the heart as the seat of sin. We can thoroughly understand that in terms of the unregenerate heart. It has to be affirmed comprehensively. Desperately wicked, Who can understand it?
Remember, a part of the new covenant is being promised a new heart. In one sense the answer is no. It's not the same heart. This is a heart that has been converted and regenerated. It's a new heart. But sanctification is a process. Justification is punctiliar; but sanctification is a process, and it is not an end unto itself. Our sanctification is only completed in our glorification, and that is yet to come.
Glorification is accomplished in Christ, as Paul makes clear in Romans 8; but, applied to us, it's something for which we are still waiting. And so our heart can still deceive us. We as Christians understand—perhaps as a sign of maturity, not of immaturity—that at times we can't explain our own hearts.
Those who have a new heart in Christ know that we are to guard against our hearts leading us astray. Instead, we are to lean into Jesus and to obey Christ and His Word. There's a distinction, but in some sense, the answer to that has to be yes and no. But thanks be to God the final verdict is no.
Lightly edited for readability, this is a transcript of Albert Mohler's answer given at our 2017 National Conference. To ask Ligonier a biblical or theological question, just visit Ask.Ligonier.org or message us on Facebook or Twitter.