Romans 5:1 in many translations, including the ESV, reads: “Therefore, since we have been justified by faith, we have peace with God through our Lord Jesus Christ.”
There is a variant reading with this passage, however, and some manuscripts say instead “since we have been justified by faith, let us have peace with God.” In the first reading, peace with God is an absolute reality following from justification. In the second, it sounds as though, even though we are justified, we may have times where we are not “at peace” (or, complete peace) with God, and thus need to seek a state of complete peace with God, and our justification enables this.
Many people say both are true. While we do have peace with God because of justification, it seems as though we can disrupt our fellowship with God through sin. Not our acceptance (and thus ultimate peace) with God, but our fellowship and experience of that peace. While I think that distinction needs to be refined somewhat, there is probably something to it.
But what did Paul have in mind here? Did he have that distinction in mind, or was he making an unqualified statement about the perfect, unfailing, and infallible and unchanging rock-bottom peace and acceptance we have with God because of our justification, which continues even if our fellowship is disrupted through sin?
I think he was making the unqualified statement, because Romans 5:1 is a clear echo of Romans 8:1, which is unqualified. Romans 5:1 states it positively: “We have peace with God.” Romans 8:1 states the flip side: “There is therefore now no condemnation for those who are in Christ Jesus.”
Romans 5:1 and Romans 8:1 are restatements of one another. Each tells us the same truth, from different sides of the coin. To have peace with God (Romans 5:1) means, conversely, having no condemnation before him (Romans 8:1). Likewise, if we have no condemnation before him (Romans 8:1), then we are at utter and complete peace with him (Romans 5:1).
There is no textual variant with Romans 8:1 — it unquestionably states that we now have no condemnation. Hence, it is most likely the case that the parallel statement in Romans 5:1 is stating the same thing — that we now have peace with God, having been justified by faith.
Why does this matter? First, because it is important in itself to know what the correct reading of any text is. Beyond this, however, it gives power in the fight against sin and provides a foundation for true humility. For no matter how diligent you are to confess your sins and turn against them (as you ought to be diligent to do!), it is always the case that our sin is greater than we realize at any point in time.
The radical affirmation of Romans 5:1 (and Romans 8:1) is that our full and complete acceptance with God comes fully through faith, and not on our ability to fully see the depth of our sin in all respects which, this side of glory, is probably not fully possible. Thus, a correct understanding of Romans 5:1 keeps us from the pride of thinking that even our experience of fellowship with God is ultimately due to our own diligence in and ability to see the full depth of our sins.
In other words, it means that even the experience of fellowship with God is available to imperfect people. This is truly stunning, if you think about it.