Out of our twentieth-century culture there has come a familiar expression, "getting a fix." This term usually refers to taking drugs. Because of his dependency upon artificial stimulants, the drug addict is continually in the position of craving a "fix."
In this verse, David states the person who trusts in God is never really afraid because his heart is "fixed" on the Lord. That's good news for us today, because in our society it seems that everyone has a dependency of some kind.
Materialistic people are dependent upon money for their happiness. Egocentric performing artists must have a continual supply of adulation and applause from their adoring fans.
Authority figures are driven by a consuming hunger for power. Perverts have an insatiable appetite for "kinky" sex. Alcoholics lust after liquor to slake their never-ending thirst. Smokers crave nicotine constantly.
We Christians are dependent also. The difference is, we look to the Lord as our sole supply. Our dependence is on Him.
This is not a mark of weakness; it is a mark of intelligence. Our reliance is upon the only absolutely dependable thing in the universe: the Lord Jesus Christ. Our heart is "fixed," because we trust in Him.
Excerpt permission granted by Harrison House Publishers