Have you come to raise the dead?
The act of literally reviving a living thing after it has already died. It is debated whether or not this is actually possible, with science generally saying a resounding "No" but religion saying "Yes."
This particular verse is tinged with allusions to Christianity, which makes sense, since raising the dead is a major tenet of the religion.
Christians believe that, during his lifetime, Jesus raised three people from the dead. They are the only son of a widow from Nain (Luke 7:11-14), the daughter of the religious leader Jairus (Mark 5:22-43), and Lazarus (John 11:1-44).
Most importantly, when Jesus was later crucified and died on the cross, Christians believe that three days later, on Easter Sunday, God raised Jesus, his son, from the dead to eternal life.
Have you come here to play Jesus?
Jesus is, obviously, he Christian savior. You might have heard of him.
Jesus of Nazareth's biography has been interpreted in different ways by different religions. Interestingly, his entire adolescence and early adulthood is never mentioned in the Bible, leaving a lot of holes and questions for us. But what we do know is this: Jesus of Nazareth was born a Jew in the town of Bethlehem during the reign of King Herod.
Herod was a nasty guy and wanted to kill all the children who were born to the Jews, so Jesus' parents, Mary and Joseph snuck out to a manger in Bethlehem to have the baby. Christian scripture maintains that Mary was impregnated by God via immaculate conception (i.e., no sex), and thus Joseph didn't really have much to do with Jesus' creation. Whatever the case, young Jesus grew up and studied carpentry and scripture under the high priests or Pharisees, of the great Temple in Jerusalem (which was later destroyed and rebuilt, twice).
After age 12, we don't hear from Jesus again until he's about 30, by which time he'd gathered a large group of followers beginning with his twelve Apostles. He traveled all over Galilee, preaching that God is his Father and that everyone should love each other no matter what and never kill, steal, lie, cheat, etc. He performed many miracles, including making blind people see, turning water into wine, and curing a leper.
To the lepers in your head
Leprosy is a very serious disease that causes skin lesions. Leprosy literally disfigures your body parts until they have to be amputated. It used to affect millions of people worldwide. Nowadays, many treatments exist, and it is no longer a huge problem.
Leprosy has been afflicting humanity for over 4,000 years. Most people are naturally immune to it, but if you spend too much time in close contact with someone who has it, you could very well contract the bacteria.
Back in the day, lepers were cast out from society and forced to live in colonies by themselves in remote areas. One of the most famous leper colonies was the island of Molokai off the coast of Maui in Hawaii. A kind-hearted priest, Father Damien, decided of his own accord to bless and care for the lepers there.
He eventually contracted the disease and died. In the Bible, Jesus heals lepers (among his other miracles).
Love's a higher law
A higher law is a type of law that supersedes normal human laws and is cast in the realm of the divine.
The Free Online Dictionary defines "higher law" as a moral or religious principle that takes precedence over the constitutions or statutes of society. Basically, it is a law that is above the law, because it is a law ordained by God.
When Bono sings this line, he refers to the fact that many people believe that love goes beyond the mortal realm, that it is divinely inspired within us, and that it is connected to the divine.