I know not whence this cometh, but ATR says with reference to Rom 12:15:
"This construction (the anarthrous attributive) is not so
common as the other uses of the participle, and yet it
is not so wholly absent from the NT ... Acts 2:2 ...
Rev 4:1." (p 1105)
He goes on to say, "It is not always easy to draw the line between the
anarthrous attributive participle and the predicate participle of
additional statement."
Certainly in this passage, however, where XAIRONTWN and KLAIONTWN are
sandwiched in between TOUS DIWKONTAS (v. 14) and TOIS TAPEINOIS (v. 16),
it seems these participles should likewise be taken attributively or
substantivally.
If, on the other hand, the anarthrous participles in v. 15 are to be
taken adverbially ("rejoice with rejoicing; weep with weeping"), what are
we to make of this? What, if any, would be the argument for such?
An additional interesting observation is that the infinitives in v. 15
and the participles in v. 16 are both to be taken imperativally in
parallel with the imperatives of v. 14, EULOGEITE and KATARASQE.
Paul S. Dixon