“Jonathan Edwards said of the law, ‘There is perhaps no part of divinity attended with so much intricacy, and wherein orthodox divines do so much differ as stating the precise agreement and difference between the two dispensations of Moses and Christ.’
“How can it be, for example, that the psalmist found the law to be a tree of life (cf. Psalm 1) whereas Paul found it a sword of death (cf. Romans 7)? The difference is partially due to the fact that the pious psalmist was an elect saint already participating in the provisions of the everlasting covenant (cf. Jer 31:31-34): He knew God (Ps 9:10), had a regenerate heart (119:11), and knew the forgiveness of sin (32:1). Paul, on the other hand, was part of that elect nation that was circumcised in the flesh but not in heart, that was striving to justify and sanctify itself through the law apart from the Spirit and faith. For sinners the hammer-blows of the law forge them into saints by driving them to the gospel of redemption. For saints, by contrast, the law is more therapeutic and sweeter than honey, than honey from the comb (19:10). For unregenerate sinners, gospel follows law; for regenerate saints, law and gospel are inseparable as they fulfill the law both in their justification and sanctification through faith in Christ” (Bruce Waltke; “Evangelical Spirituality: A Biblical Scholar’s Perspective;” JETS 31:1 (March 1988), 20-21).