A.T. Robertson Commentary Luke 8:17

"For nothing is hid, that shall not be made manifest; nor [anything] secret, that shall not be known and come to light." — Luke 8:17 (ASV)

That shall not be known (ο ου μη γνωσθη). Peculiar to Luke. First aorist passive subjunctive of γινωσκω with the strong double negative ου μη. See on Mr 4:22 for discussion of κρυπτον and αποκρυφον.