The Book of Genesis is a book of beginnings, a book of origins. From it we learn the beginning of creation, of humanity, and of the Israelites.

The Israelites originate as a people from the great Old Testament patriarch Abraham and his wife Sarah. Abraham is called forth by God from the life he knew and sets out on a journey that God promises will take him to lands that will become the homeland for his descendants who, God promises, will be a great nation “as numerous as a stars in the heavens.”

In today’s Scripture this promise is literally cut in a sacrifice and becomes a covenant between God and Abraham. A covenant is best understood for our purposes as a relationship, a relationship that goes much deeper than merely a legal contract. The sacrifice indicates the depth of the relationship between God and Abraham; it is a matter of life and death.

In the aftermath of this sacrifice, Abraham has a frightening mystical experience, where God makes his presence known to him, a presence Abraham encounters as a “deep terrifying darkness.”

It is in that terrifying darkness that Abraham comes to terms with the unknowability of God, for the God of the Old Testament is vividly mysterious, an indication that he cannot be confined like the gods of the pagans to a place or manipulated through spells and incantations. The God of the Bible does not need the sacrifices that are offered and it is not our sacrifices or worship that sustain him, as they did the gods of Abraham’s ancestors. Instead, the God of the Bible is the subverter of magic or controlled for our own purposes. His sacrifices are accepted as signs and symbols of the relationship he has with his people, and he needs none of them to be who he is. But we need these sacrifices to remind us who we are, and that there is no true love or relationship without sacrifice. The deep mystery of this God, the one true God, overtakes Abraham with terror.

But this is not the only reason for Abraham’s terror.

Abraham experiences for himself the vulnerability of genuine faith. We Christians too often pay lip service to faith, making it merely an emotional comfort, or using faith as a declaration of our tribal identity. But while comfort might come to us as a result of faith, and faith can and should order our way of life, it is not in the superficiality of our emotions or our identity that makes for authentic faith.

Faith is most raw and real when, like the experience of Abraham, we come to terms with the reality of God rather than the idols of him that we so often create out of our desires and fears. Further, faith is authentic and true when, like Abraham’s faith, it is professed as an act of trust in promises that remain outside of our ability to manipulate or control and that have indefinite and unexpected outcomes.

Faith is not magic; it is not a way of currying favor with God so that we can get what we want. Faith is an expression of our relationship with God, an act of trust, that what he has promised will be fulfilled.

We Christians profess our faith in Christ and the promises he makes to us concern not just our lives in this world, but beyond this world—beyond our death. We become, through this act of faith, his chosen people, a new kind of Israelite. And it is through us, incorporated as spiritual descendants of ancient Abraham, that God’s promises to Abraham are fulfilled.

This act of faith originates in the terrifying darkness of the Cross and it is cut in the sacrifice of his Body and his Blood. We experience this in the Mass, for the Mass is not just our community gathered to pray or a cultural pageant; rather, the Mass is the Church, the new Israelites gathered together in an encounter with the one, true, and living God, who makes himself known to us in the mystery of the Blessed Sacrament and gives his sacrifice to us as a new covenant, a new relationship that God presents to us with the gravity and severity of a matter of life and death—his life and death, our life and death. It is through this life and death that God’s promises to us in Christ are fulfilled.

And in this life and death there is mystery and there is terror, and there is also the presence of the living and true God.

The second Scripture is an excerpt from St. Paul’s letter to the Philippians, and in this text the Apostle Paul reminds us of the promises of Christ: that in Christ we are given a life beyond the life that we have now; that this life, this world, indeed our very bodies are not ends in themselves, but are a means by which God will grant to us an even greater life, even greater world, and even greater bodies than what we currently possess. We Christians call this heaven, which is not merely a place, but the event of our transformation from death to glory. It is the resurrection of the Lord Jesus from the dead that engenders in us trust that God in Christ will accomplish for us what he revealed in his body risen from the dead.

St. Paul also testifies that this act of faith in Christ makes us different, and this difference should be evident in the manner that we live, in our unique way of life. Christians are not meant to be like everyone else, but also hold to specific values and behaviors that mark us as being different from the cultures in which we live, values that are meant to indicate to ourselves and others that our faith is not in politics, economics, or culture, but in Christ.

This is unsettling to many people; indeed, it is unsettling to many Christians. The great temptation in every age of the Church’s life is accommodate ourselves to the cultures in which we live, to make ourselves acceptable and our way of life no different than the cultural, political, or economic expectations of our time and place. We Christians do this out of fear or frustration or even because we think it makes our faith more acceptable to those who might refuse or misunderstand us. But whatever our reasons and justifications, St. Paul insists that we lose much—indeed, the world loses much—if we Christians are unwilling to be who Christ intends for us to be.

Finally, the disciples of the Lord Jesus witness an extraordinary revelation. Christ reveals his glory, which is the glory of God. Remember, Christians, the great mystery of Christ is not the revelation of a spiritual teaching or political reform, but the mysterious revelation that God has accepted for himself a human nature and lived a real, human life. This is who the Lord Jesus is—not a social reformer or religious guru. Christ is God in our flesh; God in a human body; God become man. Jesus Christ is God who meets us face to face.

The mystical experience of Abraham from the Book of Genesis foreshadows what today’s Gospel describes; Christ’s disciples take the place of Abraham, and God in Christ reveals himself not in darkness but in radiant light.

Christians are meant to be witnesses to the truth of God in Christ. This truth is not a concept or an idea, but it is testimony to his person, testimony to who Jesus Christ really and truly is. Christians are meant to be the ones who God has assigned the mission of inviting the world to know who he really and truly is and sharing with others the gifts God gives to us in Christ. The greatest of these gifts is a relationship, a covenant with Christ that he gives to us in the Church.

If we Christians are to be true to who God intends for us to be, then we must set about knowing Jesus, and knowing him not just as a significant historical figure, but as a living, divine person, as the one, true God. There is no other Jesus than this. We might be more comfortable with a Jesus of our own making, or a Jesus much less than who he reveals himself to be. But the truth of Christ’s revelation is not meant to make us comfortable, but to make us holy; to transform us; to make us who God intends for us to be.

If we do not know Christ, we cannot truly be Christians. If we cannot accept Christ for who he really and truly is, then we will not accept the way of life he offers. Knowing and accepting Jesus for who he really and truly is—this is the challenge the Gospel places before us today.