I love the Amplified version of this verse. It says so much! I've been a Christian for over 20 years and I can honestly count on one hand the number of believers I've met who actually appear to be working on their walk with God in an attitude of awe and trembling. Have you? Maybe it's because most of us have had the gospel drilled into us since birth and we are comfy with it. Maybe it's because most pastors today prefer to preach on God's grace and mercy and how He is the one who saves us, not ourselves, how He is the one who is our strength. All true, of course. But the Bible is also clear that we have an obligation as well in the deal. Not in getting saved, but in growing in that salvation.
We have a choice. We can remain like whiny babies or we can grow to mature adults in Christ. Paul describes it perfectly in Hebrews 5
For everyone who continues to feed on milk is obviously inexperienced and unskilled in the doctrine of righteousness (of conformity to the divine will in purpose, thought, and action), for he is a mere infant [not able to talk yet]!
But solid food is for full-grown men, for those whose senses and mental faculties are trained by practice to discriminate and distinguish between what is morally good and noble and what is evil and contrary either to divine or human law.
Let's face it, there's an awful lot of Christian babies in America. Year after year they face the same struggles with the same complaining attitude. Their faith never grows, they blame God for their faults, and they constantly seek the wisdom of their pastor or elders to help solve their problems.
The truth is, as Paul says above, you can't just get saved, go to church on Sunday, lift up an occasional prayer and expect to get anywhere in your walk with God. Yes, you'll end up in heaven. But how much will you have missed? Yes, you are saved by Grace, but you will only grow by two things: God's Spirit and your efforts. And they must work together. Many will balk at this because we've all been taught that God does all the work and we don't have to do anything. Sounds really nice, doesn't it? But that's not what the Bible preaches. I encourage you to read Ephesians 5. The entire chapter is filled with instructions on how to become like God. Why give us instructions if we aren't supposed to do them? If we are just supposed to say. "Okay, God. Make this happen in my life."
Verse 15 of that chapter says it all.
Look carefully then how you walk! Live purposefully and worthily and accurately, not as the unwise and witless, but as wise (sensible, intelligent people).
In other words, be good on purpose. Stay in the Word of God (Find out what He's like and what He wants) and then live that out with determination (along with some added fear and trembling). Let's face it, none of us are very good people at heart. We are all selfish and capable of extreme evil. Yes, God can give us the strength to change and the power to become like Him, but we have to, as Paul says above, live purposefully.