As sermons go, it was not the kind of pulpit performance that -- when it was given -- created a buzz in the pews. The young Catholic priest's voice was flat and subdued, his face calm but not expressive.

After all, he was only a year or so into his priesthood and preaching was still rather new to him. On this day he was working with a sobering text from the Gospel of Luke in which Jesus looks over the city of Jerusalem and weeps, knowing that death and destruction looms in the future.

So that was what Father Kenneth Walker preached about, in a sermon captured on video that has gone viral on the Internet in the days after he was gunned down, at 28 years of age, by a burglar at Mother of Mercy Mission parish near downtown Phoenix. He talked about forgiveness and the need for people living in a sinful, broken and violent world to realize that they may not have much time remaining to get right with God.

"God is all merciful, but he is also perfectly just," he said. "He will not prevent something from happening, if we bring it about by our own choosing. Nevertheless, God gives time and opportunity to repent before he lets the consequences fall upon us."

The Bible and church history are full of cases in which God warns people to flee wickedness, he said. In some cases, saints and martyrs suffered and died while God gave a wayward land more time to repent.

"We are in a similar situation today, since we are now living in a world that is increasingly rejecting Christ and casting him out of the public forum," said Walker. "We have grown far too attached to our own knowledge, our technology and our worldly pleasures -- such that we have forgotten God and what he has done for us."

Look around, he said. These are troubling times for Catholics who strive to practice the ancient traditions of their faith.