According to Christian belief, God so loved the world that he sent his only begotten son to serve as a human sacrifice to atone for the sins of humanity. In return, Christians are expected to return that love. Not only are they to love God and his son, but their neighbors and even their enemies.
What form is that reciprocal love of humans for God to take? Judging by God's own actions, sacrificing one's children would seem to be the only adequate response. After all, this is what God himself did, and what he asked of Abraham. I can't understand how Christians got the idea that God wants them to block abortion clinics in the name of some imaginary notion of "sanctity of life" that can be found nowhere in biblical or Christian history. If they really followed the directions of the God of Abraham and Jesus, Sunday morning services would contain another ritual: Just before the collection, Christians would lay their first-born on the sacrificial altar.
Obviously the biblical idea of sacrificing one's children did not take hold, even in the early church. Instead Jesus himself is ritually eaten and his blood drunk. This is still pretty grisly and pagan, but at least only symbolic. And, it's a lot more convenient than sacrificing your first-born.
So how does the Christian return God's love? God loved the world, and Christians love themselves. Christianity did not become the 2,000 year success story it is by expecting people to make sacrifices. Quite the contrary. Christianity thrives for only one reason: the promise of the ultimate reward of eternal life. And the people who call themselves Christians do so because they want to live forever.
What kind of people want to live forever? Not those who love God. Not those who love their families or country. Not those who love the world. If they truly love any of these things they would not care about eternal life, which is, after all, a very selfish desire.
How does one measure love? Today we use the word far more loosely than in the past, in ways that degrade and trivialize the concept. The words "I love you" are easy to say, to get your girlfriend in bed or to quiet your spouse's rampage. But the simple profession of love does not confirm its existence. I would argue that the reality of love has only one valid test: The person doing the loving must place the well-being of the loved one ahead of his own.
The father who gives his life to save his drowning child, the mother who forgoes a career to raise her children, the soldier who jumps on the hand grenade to save his buddies - these are the people who love someone greater than they love themselves. In this, I agree with the message of the bible and Christianity, for this is nothing more than the message that we have heard from great sages throughout the ages: Only by personal sacrifice can we demonstrate our love for someone or something outside ourselves. Jesus was not the only one to say this. Zoroaster said it too, as did Confucius and Mohammed. The clearest expression of the concept, however, came from the Buddha who taught that the human being can only become at peace with the apparent hopeless reality of life by a complete rejection of self.
But, alas, rejection of self seems to be genetically impossible for the bulk of the human race. We have been programmed by our genes for individual survival, as a practical means for optimizing species survival. So even Buddhism had to find other means to capture the hearts of its followers, with rituals and superstitious teachings. Christianity managed to grow to the largest and most successful religion by a clever stratagem, borrowed from Hinduism and Zoroastrianism and later further modified by Islam: Tell people that this world of pain, suffering, and injustice is only an illusion. Beyond matter exists an infinite world of the spirit which contains joy and immortality. And we all can partake of this gift, if only we follow the dictates of the few who have been chosen, usually by themselves, to point the way.
Only those who love themselves more than God, or family, or country, or any other entity desire life after death. Christianity is successful because it is narcissistic, and the world is full of narcissists.