Adam Clarke on Romans 16:24

The grace of our Lord - This is the conclusion of Tertius, and is similar to what St. Paul used above. Hence it is possible that Tertius wrote the whole of the 22nd, 23rd, and 24th verses, without receiving any particular instructions from St. Paul, except the bare permission to add his own salutations with those of his particular friends. There is a great deal of disagreement among the MSS. and versions relative to this verse; some rejecting it entirely, and some of those which place the following verses at the end of Rom 14:23, inserting it at the end of the 27th verse in that place. The reader who chooses may consult Wetstein and Griesbach on these discordances.