It is very difficult to separate morality and missions. This is why many a deluded Christian has felt their "own righteousness" and it has led them into a strange and ironic evangelistic zeal. (Ironic because isn't self-righteousness the antonym of the gospel?) But we understand the dynamic... having a sense of righteousness gives us that sense that we have something good to sell.
Thankfully our pastor just preached a sermon on this. The conclusion as you may be expecting was this: Christ fulfilled the law and so received the blessing that we need to be effective missionaries.
But Anna and I were wondering as we discussed the sermon: The conclusion of the sermon sounds wonderful when you are a layman. But then why don't we apply the same rule when we are sending missionaries? If we are all ambassadors for Christ, why are we especially careful that these ambassadors have their walk cleaned up? "Say we had a 20 year old lesbian daughter who was repentant, grieved, but still very disgracefully struggling? And interested in applying for missions at the same time? What would our counsel to her be?"
Would we tell her to first get help in that area of her life and then go?
The word "drive" was also used. Even if we can't agree on whether or not we should look to Christ's morality to determine our qualifications for missions, we must have Christ's righteousness be our drive for missions. Admittedly, they are not the same questions. Someone can have their drive for missions be the righteousness of Christ and still derive their qualifications for missions from a different source. We need to be careful lest we make the missions agencies out to be hypocrites.
Yet I think there is a common failure here. We often see Christ's righteousness as enough to get us right on a vertical level between us and God. But then somehow we don't think it's glorious enough, weighty enough, powerful enough to make us right on a horizontal level, as ambassadors for Christ.
Hopefully these thoughts are an encouragement to let Christ's righteousness be your justification before men as well. "All authority in heaven and on earth has been given me. Go therefore."