“This is the ‘catch-all’ Genitive, the ‘drip pan’ Genitive, the ‘black hole’ of Genitive categories that tries to suck many a Genitive into its grasp! . . . . Hence, this use of the Genitive should be a last resort. If one cannot find a narrower category to which a Genitive belongs, this is where he or she should look for solace. . . . The additional categories [of the Genitive] have exegetical value” (Greek Grammar Beyond the Basics, p. 79, and footnote 24, italics his).
“For God is my witness, how I long for you all with the affection of Christ Jesus”
μάρτυς γὰρ μου ὁ θεὸς ὡς ἐπιποθως πάντας ὑμᾶς ἐν σπλάγχνοις Χριστοῦ ᾿Ιησοῦ.