The title of this post consists of two questions. I put them together because the second question cannot be answered rightly without knowing the answer to the first question. The Genevan reformer, John Calvin, who is definitely a mixed bag for me, wisely noted at the beginning of his Institutes that in order to know ourselves we must first know God.
So before we can answer the second question, we must address the first: Who is God? How do we answer this question? Where do we begin (a methodological question)? How do we know (an epistemological question)? According to the great Athanasius, the stalwart defender of the orthodox faith in the 4th C., our speech about God must begin with God's self-revelation in the incarnate Son, the historical Jesus Christ. The incarnate Jesus is the revelation of God. He is "of one substance with the Father" (Gr., homoousios to Patri). In his flesh and blood person, he is the fullness of God in bodily form (Col 2:9). As my pal, theologian Baxter Kruger, Ph.D., loves to say (and I paraphrase): To say the name of Jesus is to say the Father's Son and it is to say that God and the cosmos are eternally bound together in union. In his incarnate nature, the Son of God is the literal union of heaven and earth. He is all that the ancient Temple represented, the meeting place between God and humankind, walking on two sandaled feet! He has breached, in bodily form, the ancient dualism between deity and materiality that not only marked Greek philosophy but has been smuggled into much classical theism (i.e., the western doctrine of God). Jesus, the Son of God, takes us directly to the Father and, therefore, directly into the heart of the triune circle of the Father who loves the Son in the Spirit and the Son who loves the Father in the Spirit. In short, to speak the name of Jesus is to move immediately into the eternal circle of the triune fellowship of love. The apostle John tells us that God is love. As I said in a previous post (One Person or Three? That post fits well with this one BTW), love is not something God does; love is not an attribute (characteristic) of God, nor is love an accident of the divine nature in the Aristotelian sense of being incidental to God's nature; rather love is constitutive of that nature. God is love.
Now, what does God's essential nature of love have to do with the reason you and I were born? Because God has freely and sovereignly chosen to reveal his eternal threefold nature in time and space, that is, in the "economy" (oikonomia) of salvation, as the Father who loves the Son in the Spirit, we can make inferences as to why the God who is love creates. Since God exists eternally as a communal fellowship (koinonia) of eternal love, we can infer that there is no necessity in God's act of creation. In other words, God does not create from any lack or need in the Godhead. God does not need us for companionship, for he already exists in an eternal community of reciprocal love. Since God does not create out of necessity, we can conclude that creation itself arises from God's gracious, freely chosen act to be God for us. As Karl Barth says, from eternity past God determined that he would not be God without us. Before the creation of the world, God chose to include the human race in his triune circle of love. As the apostle Paul states, he predestined us to adoption (Eph 1:3-5). Moreover, nothing will stop God from achieving his eternal purpose for humanity, not even the sin of Adam. Even in the face of God's "No!" to sin, God's eternal "Yes!" to mankind remains, its clarion call undiminished by our shortcomings and failures. From eternity past, eons before the sin of Adam, the Father purposed to send his Son to unite divinity with creation so that the entire cosmos could forever be included in the triune circle of love. After all, what else is love to do. By its very nature, love is not self-centered; it is other-centered. Therefore, as an eternal fellowship of love, God freely and graciously chooses to extend the triune circle of fellowship to include the cosmos, and with it, all humanity.
With the stunning realization that God freely chooses to be God for us comes the equally stunning revelation that we are here on this earth in order to be included in the eternal great dance of the Father, Son and Spirit. So why were you born? You were born in order to share eternally in the blissful, joyous, perfectly harmonious and overflowing fellowship of the triune love of God. This is God's gracious gift to you and me, and like any real gift from a loving Giver, it is not conditioned upon our performance. God himself provided for us all the "performance" that was needed in the birth, life, death, resurrection, and ascension of our Lord Jesus Christ. All God asks of us is to enjoy and to share with one another the gift of love that the Father, Son and Spirit have so lavishly poured out upon us. And that's what I call Good News! Amen.