The phrase “let go and let God” can be taken a couple of ways. One is to passively sit back and simply allow things to happen. Kind of like the fatalistic "Que sera sera" (Whatever will be, will be). With this kind of attitude we are saying, "there's nothing I can do, so why try?"
The other way to take the phrase is to stop trying to control our circumstances and trust in God to control them.
So let’s take a look and see which interpretation is biblical. Remember that I said the phrase “let go and let God” is not in the Bible however that doesn’t mean that its basis or the intent of the phrase isn’t biblical.
It is absolutely true that God is sovereign and in control of everything, however the “whatever will be,will be” approach is definitely not biblical. For example we are commanded to “work out our own salvation with fear and trembling”;
Philippians 2:12 NLT Dear friends, you always followed my instructions when I was with you. And now that I am away, it is even more important. Work hard to show the results of your salvation, obeying God with deep reverence and fear.
“fight the good fight of faith”
1 Timothy 6:12 NLT Fight the good fight for the true faith. Hold tightly to the eternal life to which God has called you, which you have declared so well before many witnesses.
“put on the armor of God”
Ephesians 6:10-11 NLT A final word: Be strong in the Lord and in his mighty power. Put on all of God’s armor so that you will be able to stand firm against all strategies of the devil.
These are just three examples in the Scripture that say that we have a responsibility to do something, not just sit back and watch things happen. So the passive interpretation of "Let go and let God" is certainly not the right thing to do.
The Christian life, is a spiritual battle and the Bible tells us to prepare for it and to fight diligently. Letting go, in the sense of just sitting back and watching events unfold is not biblical.
Although there are things that we are to do we need to understand that in order to succeed they must be done in the power of God and not on our own steam. Jesus very was clear that, apart from Him, we can do nothing. We can’t do anything of eternal value apart from Christ and the power of the indwelling Holy Spirit.
John 15:5 NLT “Yes, I am the vine; you are the branches. Those who remain in me, and I in them, will produce much fruit. For apart from me you can do nothing.
John 14:26 NLT But when the Father sends the Advocate as my representative—that is, the Holy Spirit—he will teach you everything and will remind you of everything I have told you.
We can do “lots of stuff” and assume we’re doing it for God, but if we are doing it on our own power, we get the credit, and there is little or no eternal value to it. We are simply a conduit through which Christ displays His, not our, fruit.
Jesus said that we are to strive, which means to make great efforts to achieve or obtain something. If we “let go and let God” then that means that we have stopped striving.
Luke 13:24 NLT “Work hard to enter the narrow door to God’s Kingdom, for many will try to enter but will fail.
Striving means that we are diligent, active, and earnest and that we should make every effort to overcome our sinful tendencies, in order to prove that we are truly His children. We are also to strive to do the work of the kingdom, whatever form that takes in our lives. This is the reason He gives us spiritual gifts, so that we can edify one another and bring glory to Him.
We also have the responsibility to do the work that He has provided for us.
Ephesians 2:10 NLT For we are God’s masterpiece. He has created us anew in Christ Jesus, so we can do the good things he planned for us long ago.
These good works aren’t just religious activities, These good works are encompass our entire lives, everything that we do by God’s grace and for His purposes.
This means that your good works can include what you do at work, in school, and in your community. If you're a supervisor or manager, part of your good works involve the way you manage your employees. If you're a parent, your good works include what you do for and with your children.
There is also a positive reason for struggling. It’s good for us and it’s God’s plan to grow and mature us into the people He wants us to be. Struggles are just one of the ways He strengthens us for the hard things life throws at us. Each struggle makes us stronger and better able to handle the next one. Struggles show us and others that our faith is real.
1 Peter 1:6-7 NLT So be truly glad. There is wonderful joy ahead, even though you must endure many trials for a little while. These trials will show that your faith is genuine. It is being tested as fire tests and purifies gold—though your faith is far more precious than mere gold. So when your faith remains strong through many trials, it will bring you much praise and glory and honor on the day when Jesus Christ is revealed to the whole world.
So, if "Let go and let God" means that we don't try to control our situation or meet our needs in our own strength but surrender to God in His sovereignty, it is definitely biblical. It is also very hard to do. As a matter of fact, it is impossible to do without God's enabling us to do it. In God's power, we can surrender to Him and actually "Let go and let God."