Psalm 127:1  A Song of Ascents. Of Solomon. 
Unless the LORD builds the house, those who build it labor in vain. 
When is it that the LORD "builds the house"? Obviously if the LORD doesn't, no matter how well the labourers build and how grand it is, there's no guarantee that it will stand, or even that God Himself won't dismantle it! The answer: The LORD "builds the house" when His children build obediently in faith under His instruction.
We're not sure when Solomon wrote this Psalm. But although his house was the greatest recorded kingdom, God raised adversaries to his throne and shattered his glorious house. Can you imagine how strongly this verse was impressed on him!
We have the unsurpassed privilege of Building God's House. May our labours be under His instruction, and by His Power, and may this work stand forever!