There is a big difference between believing IN God and BELIEVING God. James pointed out the difference when he wrote, “You believe there is one God… even the demons do that much” (James 2:19). Demons believe IN God but obviously don’t serve Him. See the difference?
Many people are casual believers IN God. They will pray a polite prayer at the Thanksgiving meal, and attend church services on Christmas and Easter. But God doesn’t affect their lives or their spending habits. He doesn’t curb their morality, keep them from cursing on the job, gossiping, or telling a lie to get ahead. They believe IN God but still do pretty much what they want.
Another kind of belief is the convenient believer. This is the person who waves the Christian flag whenever it involves personal benefit. Such a person is quick to talk God-talk if it helps seal a business deal, or score a date, or land a promotion. This person uses their belief IN God to leverage circumstances for personal benefit.
The third kind of belief is the committed believer. This is what Jesus calls us to.... and represents what a true Christ-follower looks like. The road to commitment is paved with personal abandonment and self-denial. Life ceases to be (less) about us, and begins to be more about God. The committed believer doesn’t waver because of adverse circumstances. He is not moved by other’s opinions. He is a Christ-follower all the time. Obedience and faithfulness are his goals. 90% commitment to Christ is not enough for this person.