इति ते ज्ञानमाख्यातं गुह्याद्गुह्यतरं मया। विमृश्यैतदशेषेण यथेच्छसि तथा कुरु ॥

iti te jñānam ākhyātaṁ guhyād guhyataraṁ mayā vimṛiśhyaitad aśheṣheṇa yathechchhasi tathā kuru

Thus hath wisdom, more secret than secrecy itself, been declared unto thee by Me; having reflected on it fully, then act thou as thou listest.

In plain words: Krishna says he has now shared wisdom more secret than any secret. He tells Arjuna to think it over carefully and then choose for himself what to do.