Unless the LORD builds the house, those who build it labor in vain. Unless the LORD watches over the city, the watchman stays awake in vain.
[Psalm 127:1]
What makes a house built apart from God a work of vanity? Or what makes watching over a city without him useless?
This verse reminds me of Gamaliel’s advice before the Jewish council about what to do with the apostles who had filled Jerusalem with their teaching:
So in the present case I tell you, keep away from these men and let them alone, for if this plan or this undertaking is of man, it will fail; 39 but if it is of God, you will not be able to overthrow them. You might even be found opposing God! (Acts 5:38-39)
Gamaliel had the insight to see that what ultimately matters and ultimately lasts is the will of God. Therefore, to do anything without consulting him first and making sure you have his support is bad business. It will fail. And more than that: your work will be found contrary to God’s will (cf. Matthew 12:30)!
This means that doing your own thing in life is not only a colossal waste of time and effort. It is also outright rebellion against the One who owns and supplies all of your life, strength, and resources.
But praise God for providing a better way: “Commit your work to the Lord, and your plans will be established” (Proverbs 16:4).