Actionable intelligence, information and knowledge must precede our actions.

For I know the thought I think towards you...Jer 29:11 clearly reveals that God had some form of definite knowledge about what He was talking about.
A child who tells his friend that no matter what I do my dad will never beat me is coming from certain knowledge and experience. Also, a car manufacturer tells you what the car can do: 200 miles per hour, double exhaust, a V8 engine, deserts and rocky hills friendly and so on, speaking from a certain depth of knowledge. It will therefore be wise to take God at His word "knowing" who has spoken.

The doors that were shut against you led you to greater discoveries, so now you know certain things about closed doors and opportunities. The Apostle Paul said in Romans 8:28," And we know "that all things works together for good..."
There's a point you get to in your relationship with the Holy Spirit where you are so double sure about things that aren't apparent to others and then you declare it with absolute faith and see divine manifestations all around.

Jesus knew that as long as those naysayers were around him they wouldn't allow his faith to flow freely so he had to send them out. Only those who wouldn't drain or stop the flow of virtue he allowed. This is all rooted in your Ability to Know.