As to Rom. 5:17, it is not the same as Rom. 8:4. There it is the fact that, in walking in the Spirit, the sum of the requirement of the law (and so only) would be fulfilled, the διχαίωμα. Much more, perhaps; but as the flesh was not subject to it, that διχαίωμα could not be accomplished when in the flesh. But, living in the. Spirit, the Spirit or Christ living in us, the body dead, the sum of the law's requirements, so walking, was fulfilled. Against the fruits of righteousness there was no law. The Christian has a higher rule-to be an imitator of God, as manifested in man in Christ (Eph. 5:1,2); but as people were looking for legal righteousness, what is in verses 2, 3,was the way of getting it.
Chapter 5:17 is διχαιοσύνης, the abstract thing righteousness given to us, and though taken abstractedly, that thing in its nature and quality; yet as being free gift (δωρεά), and that of God, according to grace, goes much farther than the requirement or διχαίωμα of the law, which, if fulfilled, was no more than man's -righteousness.
Ver. 16 is διχαίωμα. But it is not τὸ διχαίωμα τοῦ νόμου. That was measured by the requirement of the law. Here it is of many offenses to a sum of recognized righteousness. It is a χάρισμα-a gracious gift of a sum of adequate righteousness, judicially estimated and satisfactory. Keeping the law makes that out as a requirement from man. It would be his righteousness as rightly measured by it. But here it is a χάρισμα. χρίμα came upon men to χατάχριμα. It is now a χάρισμα. Χρἰμα dealing with many offenses, and so giving us, according to God, an adequate judicial righteousness, but now, according to God's free gift, not man's responsibility; the διχαίωμα of the law and God's διχαίωμα are different. We have hardly words in English to make these differences, but διχαίωμα is the sum of requirement, διχαιοσνη the thing righteousness; so 1 Cor. 1:30. Hence, in Rom. 4, it is διχαιοσύνη; διχαιοσύνη is ἐλογίσθη. These words in -οσύνη are the quality. Then the persons of the perfect passive, as a rule, give the thing done, the doing, and the doer, χρίμα, χρίσις, χριτής, διχαίωηα, διχαίωοις. We have not διχαἰωτης. It is not an office like χριτής but διχαιῶν (Rom. 3:26;4. 5).
" The fruits of righteousness," in Philip. 1: 11, must not be taken as if meaning righteousness itself as fruits. As you could not say that " fruit of the Spirit" (Gal. 5:22) was the Spirit as fruit, or "fruit of the light" (Eph. 5:24) meant the light as fruit, so you cannot say that " the fruits of righteousness " means righteousness as fruits, but the fruits which flow from a righteous moral state. See also James 3:18; Heb. 12:11; Rom. 6:21; Prov. 11:30. In no instance is the genitive with "fruit " the genitive of apposition, but a righteous moral condition; the moral consequence because the necessary vital expression of a state of justification of life in which a man now brings forth fruit in newness of spirit (Rom. 7: 6).