Believing in something is one thing; faith in the promises of what you believe is quite another. When you stand up, you not only believe that your feet, ankles, and knees will support and balance you, you have faith that they will. If you don't you'd hold on to whatever you could as you rose - just to be sure - then slowly test your legs to be sure they'll function as you hope.
Jarius, a Synagogue ruler, believed Jesus could heal his dying little daughter, and his faith move him to action: to find Jesus, work his way through the crowds, and fall at Jesus' feet, pleading, "Please come and put Your hands on her so that she will be healed and live." (Mark 5:23).
Jarius, whether critical of Jesus - as most Jewish leaders were - or one of the few who understood, knew enough to act on behalf of his young daughter in a time of desperate need. How about you? Who have you turned to in a time of desperate need? Was your faith rewarded?
Jesus didn't appear to care about Jarius' position as a Synagogue ruler - in fact, Jesus often preached in the Synagogues in the places He visited (see John 18:20) - so Jarius may have been one of the few who appreciated Jesus and His teaching. Regardless, Jesus was there for Jarius, as we'll see in Part II, and came when Jarius asked.
So when you're in desperate need, whether you've believed previously or not, will you believe now and in faith bring your needs to Him? Your life may be going swimmingly right now, and you don't think you need faith in anything but yourself or your job, or a relationship. Don't wait until you have a desperate need and have nowhere to turn - begin working up the faith you'll need now - build up the spiritual muscles so that when the time to stand comes, you will indeed be able to stand confidently.
How was Jarius' faith rewarded? You can read ahead or read about it in my Belief and Faith - Part II - Mark 5:35-43 post.