At some point in your walk with the Lord, you will have to see Him for yourself. Knowing who He is by faith is great, but experiencing who He is in your life is inescapable. If your desire is to truly know Him, you will have to go through something. You can't just keep hearing the testimony of others, but you need to have a testimony to share with others.
No matter how much you try to empathize with someone, until you've been there, you just can't know. As Job is saying here, we have heard of God and trusted in Him, but when we actually see Him for ourselves, we see how ridiculously inadequate our measurement was. To say you know God to be a healer when a doctor has never scratched his head over your case isn't quite right. You know God CAN heal, but do you personally know Him as a healer?
We will all have our faith tested in one area or another. It doesn't mean your faith is weak; it means God wants to develop His relationship with you. Will you be willing to repent of what you thought you knew, and accept what God shows you with your own eyes? When God Himself challenges your finite wisdom, will you humbly submit and learn what He is teaching you? When bad things happen, are you looking for the cause, or are you looking for God?