John Gill Commentary Luke 21:13

"It shall turn out unto you for a testimony." — Luke 21:13 (ASV)

And it shall turn to you for a testimony.
] By this means they would have an opportunity of leaving their testimony for Christ before kings and rulers; and what they should meet with from them, would be a means of strengthening and confirming them in the truths of the Gospel; and be a proof and evidence to them of the certainty of the above things Christ had said should be accomplished; as well as be for a testimony against the rulers and governors, Jews, and Gentiles, before whom they should be convened; see (Matthew 10:18) .