How did the Christian band Building 429 get its name?

According to Jason Roy, the band's name originated from a youth group. Roy's wife Cortni had once belonged to a youth group that had a system called the "429 Challenge," based on Ephesians 4:29. Whenever someone in the group spoke negatively about another, others were allowed to issue a verbal "four twenty-nine." This resulted in the offender having to say something nice to the person that was offended. The band members took this challenge and created a name around it - building one another up, hence, "Building 429."

https://en.wikipedia.org/wiki/Building_429