Question: Hebrews:9:27 says: "And as it is appointed unto men once to die, but after this the judgment." Lazarus of Bethany, who died physically, was resurrected and then, of course, died again. So, how many times did Lazarus die? The answer is "twice." We have other cases where Jesus gave His disciples the power to raise people from the dead who later died again physically. How are we to understand? Which is it, once or twice?
Response: As you point out, Hebrews:9:27 says, "And as it is appointed unto men once to die, but after this the judgment." "Men" is generic, speaking of all mankind. That the Lord, of His own will and sovereign choice, has, on occasion, brought back to life individuals (temporarily) does not affect this general ruling. Both Elijah and Elisha raised individuals from the dead by the power of God. Jesus raised a number of people from the dead. Again, these exceptions did not change the ruling under which humanity lives (and dies), as Hebrews:9:27 summarizes.
The fact that the Lord Jesus walked on water (Mt 14:26) or that Elisha made the head of an axe float (2 Ki:6:6) did not overturn the law of gravity. In short, we need to discern the plain meaning of the Scriptures.
This is important, as Muslim "apologists," for the sake of argument, often bring this up as "yet another contradiction" in the Bible. With careful examination of context and word meanings in Scripture, such a conclusion is insupportable. Let us strive to be diligent as we search the Scriptures daily.