six weeks off that summer to record the follow-up, Not of this World. Stylistically, the album was similar to the band's previous two releases, filled with straight-ahead rockers and garnished with radio-friendly ballads, but for the first time, the band experimented with synthesizers; however, they did not shift completely away from the Hammond B3 organ, as it was featured in several tracks ("Not of This World", "Grave Robber", "Occupy" and "Lift Him Up"). Nevertheless, the result was something of a preview of the band's direction in future albums, as Petra would embrace the heavier guitar styles that such a sound better complemented. As if to emphasize the shift, the album opened and closed with Petra's first-ever instrumental tracks: synthesized versions of the Doxology. As with the band's most recent albums, Not of This World was well received critically and commercially. By now widely recognized as the top Christian rock band in the genre's short history, the Petra formula was well in place. "Not of This World continues Petra's winning streak of great records that minister the Good News with good music," CCM Magazine wrote in praising the album. In addition, Not of This World garnered Petra its first Grammy nomination, for Best Performance By a Gospel Duo, Group, Choir or Chorus in 1985. Continuing with the trend of producing radio hits, the title track became a major radio hit during 1983 and 1984, with "Grave Robber" being a minor radio hit during that same time. "Lift Him Up" was the featured praise song on this album. The album was massively successful in the still-new world of Christian rock: It became the No. 1 Christian album in the country in February 1984, dislodging Amy Grant's Age to Age, which had held the top spot for more than a year. More than six months after its release, Not of This World remained in the top five, behind two albums by Grant and one by Sandi Patty. More Power to Ya, in its 86th week on the chart, was still in the top 10. To support Not of This World, Petra launched its biggest tour yet – 150 dates around the world with a total attendance of more than 450,000 people through the end of 1984. Headlining for the first time, Petra poured resources into creating a concert experience as dynamic as any secular rock band, using numerous lights, stage effects and costumes.