I value the Why? question. I think I’ve mostly lost the smart-alecky junior high attitude underneath the asking, but I still appreciate and utilize the interrogative shovel to dig for idealogical treasure.
The reason why God created the universe and the reason why God created marriage between one man and one woman and the reason why Christ came and died and rose again and the reason why we make disciples and the reason why every disciple belongs to the Church is the same reason. If we said that the reason is “for His glory,” we’d be correct but perhaps still clouded behind the Christian jargon. So again, why creation, marriage, salvation, and church?
It’s because the three Persons of God so loved one another and enjoyed their union together that He made other beings to know and enjoy that glory. The understanding and affection and joy between the Father, Son, and the Spirit is part of His magnificence. It’s what makes Him awesome. His incommunicable attributes such as omniscience and omnipotence and eternality are at work for spilling His communicable glory into us.
Therefore, the reason why God made the world, instituted family, forgives rebels, and knits His people together in one Body is so that we will have understanding and affection and joy with Him and between ourselves like Him.
We glorify God when we see His glory truly, when we say it accurately, and when we sing it wholeheartedly. We also glory God when we receive His gifts thankfully and then imitate Him through loving generosity/sacrifice for the joy of others and in order to increase fellowship between us. We glorify God vertically and horizontally, through praise and through practice, through communion with Him through Christ and communion with each other by the Spirit.
What did God want with us and for us? He wanted us to taste His love and joy in union with Him as well as in our relationships here, especially in family, both by blood and by Christ’s blood. Why? Because it’s truly glorious.