2 Corinthians 8:23

‘Whether any inquire about Titus, he is my partner and my fellow-worker to you-ward, or our brethren, they are the messengers of the churches, they are the glory of Christ.'

He recognises that some might well wish to check out the people he has sent. They can inform such people that Titus is Paul's partner, and the fellow-worker he has appointed to oversee the Corinthian church in his necessary absence. As for the other two they are appointed ‘apostles' of the churches. Here ‘apostles' is used in its general use as a representative, those given authority to speak and act on behalf of those who appointed them. This might serve to demonstrate that Paul only names those who are appointed by him.

‘They are the glory of Christ.' In the Old Testament ‘the glory' of a nation was its wealth and prosperity (Isaiah 10:3; Isaiah 17:3; Isaiah 21:16; Ezekiel 24:25) or its powerful armies (Isaiah 8:7). Thus this may signify that such men are Christ's wealth, Christ's battalions. They are what shows Him to be what He is, men worthy of their position who by their lives reveal His glory. They are His particular assets, His chosen vessels.

Or he may simply be saying that their status is such that it outshines all others. While ambassadors may be the glory of their country, these men are beyond that. They are unique in status, they are His glory, for they are the chosen representatives of His people, and therefore of Him, representatives of the glory that is unseen. Or alternately he may mean that they are those in whom Christ glories.

Or Paul may have in mind 2 Corinthians 3:18 and be saying that these men are of those who see Christ, as it were, face to face with unveiled eyes, and are thus those who are well on the way to attaining His glory, indeed have potentially done so. They are as much of the glory of Christ as the world can see.

What it certainly means is that in some way they outshine, and are more important than, all that is in or of the world