'Make Sure' in the Bible

Like a man hired year by year he shall deal with him; he shall not rule over him with harshness in your sight.

Therefore, believers, be all the more diligent to make certain about His calling and choosing you [be sure that your behavior reflects and confirms your relationship with God]; for by doing these things [actively developing these virtues], you will never stumble [in your spiritual growth and will live a life that leads others away from sin];