Consequently, you are no longer foreigners and aliens, but fellow citizens with God's people and members of God's household, built on the foundation of the apostles and prophets, with Christ Jesus himself as the chief cornerstone. In Him the whole building is joined together and rises to become a holy temple in the Lord. And in Him you too are being built together to become a dwelling in which God lives by His Spirit.
Too often we forget Jesus as the chief cornerstone of our spiritual foundation. The one who joins us all together to be a holy temple for the Lord. If we leave out that chief cornerstone and put our focus on anything else (no matter how "good" it may be), we are building on perishable, unstable materials. No matter how beautiful it may look on the outside, the inside is unstable and condemned. It will not last, it will fall and crumble into ashes.
More times than I can count the Lord has revealed to me that I am once again building upon the wrong foundation. I need to keep my focus on Jesus. Doctrine, the church I attend, rules I follow, good works I do - none of them mean anything if my focus and motivation is not Jesus.