Albert Barnes on Romans 16:19

For your obedience, etc. Rom 1:8. Your mild, obedient disposition to learn, and to obey the precepts of the teachers of religion.

I am glad, etc. I rejoice that you evince such a disposition. But he immediately adds, that this was just the temper to be imposed upon, and cautions them against that danger.

Wise unto that which is good. Evince understanding of that which is adapted to promote good and worthy ends.

Simple concerning evil. Greek, harmless. Not disposed to do wrong; having no plan, and yielding to none of the allurements of evil. You have shown your wisdom in obeying the gospel. I would have you still evince wisdom towards every good design; but to be unacquainted with any plan of evil. Do not yield to those plans, or follow those who would lead you into them.

(a) "abroad unto all men" Rom 1:8 (b) "wise unto that which is good" Mt 10:16 (1) "simple" or, "harmless"