The vandalism was reported to authorities shortly before 7:30 a.m. Wednesday. Aside from the graffiti, there was no other physical damage.
"The police actually came to my door this morning and told me, 'there's been vandalism at the church. Come over and take a look at it,' said Pastor Sean DeFrain. "My first thought was, well you know, shock. It was clean yesterday."
DeFrain's congregation is small, with just 40 parishioners. But once the word got out, many came showed up at the church and began immediately cleaning off the messages.
"I had to get over here as soon as possible, I only have a couple little cans of Goof Off, but we're going to do what we can," said parishioner Michael Kiewert.
LAPD detectives from the West Valley Division are investigating the vandalism. They called in contractors to help in the cleanup, and by early afternoon it was all gone.
No one claimed responsibility for the vandalism, which is being treated as a hate crime by the multi-agency House of Worship Task Force, according to a Los Angeles police spokeswoman.
"There is probably some young adults who thought it would be cool to deface a church on holy week? get a reaction," said DeFrain. "They've obviously sent a message, but that message is more about the condition of their own hearts and less about my church or myself personally."
By the afternoon, strangers who heard about the vandalism began dropping by the church and leaving donations, totaling more than $1,500.
DeFrain said St. John's is ready for Easter Sunday and services will not be affected.
City News Service contributed to this report.