A couple of definitions today might be helpful right off the bat since you probably haven’t used either of these words in casual conversation today. I know I have not.

Mortification is about death. Killing sin as violently and as often as necessary. It’s waging all out war against what is contrary to life in Christ. Now anyone who has been a Christian for more than five minutes knows the reality of mortification. It was the great Puritan John Owen who famously said, “Be killing sin, or sin will be killing you.”

To put it in specifically biblical terms, we see a passage like this:

Since, then, you have been raised with Christ, set your hearts on things above, where Christ is, seated at the right hand of God. Set your minds on things above, not on earthly things. For you died, and your life is now hidden with Christ in God. When Christ, who is your life, appears, then you also will appear with him in glory.

Put to death, therefore, whatever belongs to your earthly nature: sexual immorality, impurity, lust, evil desires and greed, which is idolatry” (Col. 3:1-5).

In those verses we see first the reality – that we died when we came into Christ. And yet the remnants of that former self still cling doggedly to us, and that’s why we must also “put to death.” In other words, because we have died, we must daily die. That’s mortification, and it involves the daily battle against the self.

Vivification is more positive. Whereas mortification is about the removal of sin and its causes, vivification is about stirring up your affections for Jesus in a positive manner. It’s about reminding yourself of the beauties and excellencies found in Jesus alone.

The thing is that the two must work in harmony with each other. Think of it like this:

Let’s say that you resolve that you are going to drastically reduce the amount of time you spend looking at your phone. Now a big part of seeing that goal come to reality is the act of putting down your phone. It’s consciously choosing not to check Twitter or Instagram when you have a few free minutes. But that negative goal will only get you part of the way there.

To really press into the goal, you need to realize that you will suddenly have three or four extra hours to fill in the day if you really do put the phone down. So what will you do with it? The answer is to find something more constructive, more edifying, more useful, and more beautiful than what you are leaving behind. You need something better to fill the gap left by something worse.

And this is why we must, as Christians, be adept at both mortification and vivification.

Consider, for example, how embittered, dispassionate life would be if all we ever did as Christians was practice mortification. Like those walking around in sackcloth and ashes, we would be devoid of real joy and eternal happiness. Consider, then, for example, how unbridled life would be if all we ever practiced was vivification. Like those who treat sin as a game with no real consequences, we would see the world – and ourselves – through rose colored glasses.

They are two sides of the same coin.

We fight sin. We battle it. We kill it. But anyone who has waged this kind of war will tell you that the removal of any sinful habit, especially one we hold closely to our hearts, leaves an incredible void in its absence. We wonder if we can even go on, for we’ve come to look forward to that sin. We crave it. We think about it and nurture it.

What can fill the void left by mortification?

Vivification.

The void is not only filled, but we find ourselves overflowing. We kill and we fill. We fight and we feast. We remove and we indulge.