{Their debtors} (opheiletai aut(936e)). Objective genitive:
the Gentiles are debtors to the Jews. See the word opheilet(8873)
in  1:14  8:12 . {For if} (ei gar). Condition of the first
class, assumed as true, first aorist active indicative
(ekoin(936e)(8873)an, from koin(936e)e(935c), to share) with associative
instrumental case (pneumatikois, spiritual things). {To
minister unto} (leitourg(8873)ai, first aorist active infinitive of
leitourge(935c) with dative case autois, to them), but here
certainly with no "sacerdotal" functions (cf. verse  16 ). {In
carnal things} (en tois sarkikois). Things which belong to the
natural life of the flesh (sarx), not the sinful aspects of the
flesh at all.