Who did Les say were the 'first fruits of them that slept'?

Les explains that Christ had to be the first to be resurrected from the dead, because this had never happened before. People raised by Elijah and Elisha, and even Lazarus, were only restored to life and died again. But beginning with Christ's resurrection, the term resurrection is used in its fullest meaning. He says you cannot have a bundle of first fruits with one stem of grain; there had to be many. So he feels Matthew 27:52-53 records the sampling of believers who had died and were resurrected, walking into the city. With Christ as the first fruit, together they become the first fruits of them that slept. The first resurrection is broken down into three areas, and this first one is the first fruits: Christ and this sampling that came out of the grave and went into Jerusalem. Scripture is silent on them, but if they were resurrected, Christ had to take them on up into glory, not leave them in this old world of sin and pain.