τὸ γὰρ βραχύ τι τοῦτο πᾶσαν ὑμῶν ἔχει τὴν βεβαίωσιν καὶ πεῖραν τῆς γνώμης → this trifle contains the whole seal and trial of your resolution
nōlens: entis, Part., from nolo.
nōlēns, tis, part. pr. de nolo.