Why did the saints raised with Jesus not die again like Lazarus did?
The saints raised after Christ's resurrection did not die again because they were resurrected believers who had been given immortality, not merely restored to mortal life like Lazarus. They appeared in Jerusalem and were evidently taken up into heaven, serving as the firstfruits sheaf alongside Him.
Les explains that these saints did not come out of the grave while Christ was on the cross; they came out after He had been resurrected Himself, because Christ had to be the first to be resurrected. Then, to make the sheaf analogy come to the full, there had to be other examples of resurrection. Some Jewish believers were evidently resurrected from the cemeteries around Jerusalem, came into the city, and appeared to probably their friends and relatives. Since Christ in His resurrected body ascended into heaven, these saints did as well. They did not just come like Lazarus to die again; these were resurrected believers who had been given immortality and no doubt were taken on up into heaven. That makes the sheaf of the first fruits, the beginning of the first resurrection, and Les emphasizes first fruits plural.