These are just a few phrases that seem to be spoken when we feel that we have exhausted all of our resources. The good news is that you have available power that may be untapped in your life. When Jesus has been allowed into your daily routine, suddenly there is an abundance of strength and power that may have never been utilized before. Call it a reserve, just waiting for you to activate it.
I remember driving a borrowed pickup to Texas one time. The drive was quite a distance and I was frustrated because I had to stop several times for gas. When I arrived at my destination, the owner asked me how the trip went and I shared my sob story. Then he said, "did you use the reserve gas tank?" Say what? The truck I had driven had a second tank that could be activated with a simple switch! Knowing that ahead of time could have changed everything!
That's kind of what it feels like when you arrive at the end of your strength. When you've done everything that you can do, thats when God will step in and do what you can't do. Just flip the switch and let God take over.