In the former passage, the apostle Peter used the Greek word geʹnos, whereas in the text of Jesus’ statement, we find ge·ne·aʹ. These two Greek words may appear to be similar, and they are linked to a common root; yet, they are different words, and they have different meanings. The New World Translation of the Holy Scriptures​—With References says in a footnote to 1 Peter 2:9: “‘Race.’ Gr., geʹnos; different from ge·ne·aʹ, ‘generation,’ as in Mt 24:34.” A corresponding footnote is found to Matthew 24:34.

As those footnotes indicate, geʹnos is appropriately translated by the English word “race,” as commonly found in English versions. At 1 Peter 2:9, Peter applied the prophecy found at Isaiah 61:6 to anointed Christians with the heavenly hope. These are drawn from many nations and tribes, but natural backgrounds are put behind them as they become part of the nation of spiritual Israel. (Romans 10:12; Galatians 3:28, 29; 6:16; Revelation 5:9, 10) Peter identified them as becoming, in a spiritual sense, a distinct group​—“a chosen race, a royal priesthood, a holy nation, a people for special possession.”

But in the Greek text of Jesus’ words found at Matthew 24:34, we find the word ge·ne·aʹ. It is widely recognized that Jesus was referring, not to any “race” of people, but to the people living at a certain period of time.

Yes, in the initial fulfillment, “this generation” evidently meant the same as it did at other times​—the contemporaneous generation of unbelieving Jews. That “generation” would not pass away without experiencing what Jesus foretold. As Williamson commented, this proved true in the decades leading up to Jerusalem’s destruction, as an eyewitness historian, Josephus, described.

In the second or larger fulfillment, “this generation” would logically also be the contemporaneous people. As the article beginning on page 16 establishes, we need not conclude that Jesus was referring to a set number of years making up a “generation.”

On the contrary, two key things can be said about any time implied by “generation.” (1) A generation of people cannot be viewed as a period having a fixed number of years, as is the case with time designations meaning a set number of years (decade or century). (2) The people of a generation live for a relatively brief period, not one of great length.