Nuclei of life

If a country has government, has politics, economics, judicial force, soldiers, teachers, etc. But what is the nuclei of a country? What is the most important function in a country?
The most important, the nuclei of a country is to have all its countrymen to feel safe, to be happy, to live and enjoy their each lives.

Likewise, for a church, there is mission, there is kids ministry, LG, training, music, pastoral, sermons, etc. What is the nuclei, the most important function of a church?
The most important, the nuclei of a church is to have each member to grow to be like Him. To be more christ-like each day. And for each other to help one another to be more Christ-like.

All our activities in our church, have that in your mind. Move towards that direction. To become christ-like yourself, and to help others become christ-like as well.

Wrong example: SBY with focus of economic growth.
Church with focus of member growth

Question to ponder, what is the nuclei of our lives?