A.T. Robertson Commentary Luke 21:33

"Heaven and earth shall pass away: but my words shall not pass away." — Luke 21:33 (ASV)

My words shall not pass away (ο λογο μου ου μη παρελευσοντα). Future middle indicative with ου μη, a bit stronger statement than the subjunctive. It is noteworthy that Jesus utters these words just after the difficult prediction in verse 32.