The secret of success is constancy to purpose.
-Benjamin Disraeli

I think this is the whole clue to life. Constancy to purpose.

First, you have to get with God and discover HIS mission, HIS purpose, for your life.  This can be a major process, and a long one filled with missteps. That’s okay. If you are truly seeking God’s purpose in your life, He won’t let you down. (If any of you lacks wisdom, he should ask God, who gives generously to all without finding fault, and it will be given to him. James 1:5 NIV)

Then, you have to rely on Christ. (Philippians 4:13, I can do all things through Christ, who strengthens me.)  After all, would God put you on earth for a particular mission/purpose, then not give you the abilities, talents, desire, love, passion that you need to do it? That would be silly, and God may have a sense of humor (look at the platypus), but He is not silly!

I’ve called this concept intentionality, as well. For instance, if you noticed my status report, I’m giving up diet Coke. I’ve been drinking up to 5 sodas a day, and when you’re only 4’6", that’s NUTS! I’ve gone 48 hours without as of this afternoon, yet, when I got on the computer this morning, I literally almost got up to go get one of the last diet Cokes in the house.

Habit, habit, habit.

I had to physically stop myself and re-focus on my purpose: better health. The diet Coke is not worth the high blood sugar, the high blood pressure, the money, the caffeine headaches, etc. Once I refocused on my purpose, I could intentionally remain constant to it.

Otherwise, the bad habit would have won.  Good health would have lost.

What purpose has God placed in your life?
Are you remaining constant to it, through Christ’s power?

–who hopes the tiredness and headachyness will go away sooner rather than later.