James 1:6-8 and 4:8 tell us: "One who wavers (hesitates, doubts) is like the billowing surge out at sea, that is blown hither and thither and tossed by the wind. For truly, let not such a person imagine that he will receive anything (he asks for) from the Lord,
In Matthew 6:24 Jesus said, "No one can serve two masters. Either he will hate the one and love the other, or he will be devoted to the one and despise the other. You cannot serve both God and Money." NIV
Matthew 6:22, “The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.”
No two purposes/goals are so completely one that the service of either would not more or less detract from the service of the other.
So, how can a person become single-minded? We have the great example of the prophet Joshua. Joshua 24:14, 15, “Now therefore fear the LORD, and serve him in sincerity and in truth: and put away the gods which your fathers served…choose you this day whom ye will serve…but as for me and my house, we will serve the LORD.”
If you are struggling with temptations and trials, read James 1:2, 3,“Consider it all joy, my brethren, when you encounter various trials, knowing that the testing of your faith produces endurance.” Yes, thank God for all of your trials because you are learning not to be double minded. You are learning to ask and rely on God to help you to develop through all of your difficulties.
“Because the Sovereign LORD helps me, I will not be disgraced. Therefore have I set my face like flint, and I know I will not be put to shame.” Isaiah 50:7 NIV