When children ask their dad to catch them when they jump from a height, it isn’t a test. Children jump into their dad’s arms because they trust them. As a rule, most children do not jump where there is no trust.
It was not necessary for Jesus to jump to see it God would keep his word. He believe God when God made a promise. It’s unbelief that makes us question things. Faith has as one of its qualities, the aspect of trust. Believing God’s promises is the same as trusting God to do what he says. When Jesus calls on us to believe, he is asking us to trust him. To do what he says without wavering or doubt of any kind.
When I was young, my brother-in-law carried me out into deep water at Ocean Pond, Florida. Suddenly, he slipped out from under me. Instead of learning to swim, I panicked. I was terribly frightened, so frightened that I would not ever allow him to do that again. He lost my trust because he failed to keep me safe. When he said he wouldn’t do it again I didn’t believe him, there was major doubt in my mind.
This will never happen with God. You will never have to wonder if he will rescue you or not. In the deepest water he will never let go. Though you walk through a valley filled with shadows he will be with you every step. If you are his child he will never leave you. That’s why you don’t need to put him to the test. He never fails and so no test is needed. Satan knew this as well as Jesus did. He knows it now but he would like to put doubt in your mind. Remember what he asked Eve? “Did he really say?” In other words can you trust what God says? “Will he really save you? Will he really take you to heaven when you die? If God loves you then why do bad things happen to you?” All questions designed to cause doubt about God.
Satan wants to put doubts in our minds because he knows that doubt is the opposite of faith. How will you answer him? Maybe Luke 4:12 is your verse too.