Where do we draw the line with what we know we are capable of achieving ourselves and laying it out before God? Is there a line at all? No, there isn't. It really doesn't matter the magnitude of any decision that you have to make, we should live lives saturated in prayer and dependence upon God. One of my favorite passages of Scripture is Proverbs 3:5-6, "Trust the Lord with all your heart and don't lean on your own understanding. In all your ways acknowledge Him and He will direct your path." In these verses we are reminded that when we trust Him with everything then He will be faithful to guide us in all things.
Sure, there are some basic decisions in life that don't require that we hit our knees at that moment to decide. If you are the store, don't agonize over whether to buy Honeycomb cereal or Captain Crunch. Just make a decision. And there are times where two equally good and beneficial options are laid out in front of you. In those cases, in which God would be glorified by either decision, you must simply choose. But all of our choices must be under girded with the framework of total and absolute dependence upon God.
Many of the books in the book of Psalms are an incredible collection of the soul thoughts and songs of men who find themselves in perilous situations facing daunting decisions. These men cry out to God in the morning, afternoon, and night, seeking His guidance and strength, unwilling to commit to making decisions unless He is fully in them. Consider some of these words:
Wait for the Lord; be courageous and let your heart be strong. Wait for the Lord. (Psalm 27:14)
Commit your way to the Lord; trust in Him, and He will act. (Psalm 37:5)
God is our refuge and strength, a helper who is always found in times of trouble. Stop your fighting (be still) - and know that I am God, exalted among the nations, exalted on the earth." (Psalm 46:1, 10)There are hundreds more examples in Scripture where we are admonished to call upon the Lord for everything. When we are totally and utterly dependent upon God, we won't find ourselves in situations desperately wondering what He would have us do. That doesn't mean that all of our decisions will be simple and laid out for us. But what it does mean is that we will be powered by One greater than ourselves, One who is in complete control of our hearts and minds. When that is the case, we are no longer dependent upon our own devices but we have had our hearts and minds transformed "so that we may discern what is the good, pleasing, and perfect will of God." (Romans 12:2)