In verses 16 and 17, Paul is saying that as a result of this, we no longer look at things the way we did before. "From now on, we regard no one according to the flesh." Before, we always regarded everybody according to the flesh. Now, we regard no one according to the flesh. You see, conversion means a change of perspective has taken place. One set of conditions is passing out of the way.
That is the way conversion is. The "old" passes away. The "new" comes into its place. A process is talking place. A transformation is gradually taking place in our lives. And, as Paul describes it here, we no longer look at things according to the flesh. Now we look at things according to the Spirit. That is, a converted person does. So, a transformation is talking place—from a worldly point of view to a spiritual one. And the first step—in the context of II Corinthians 5—is to be reconciled to God.