Salàm, I read the following hadith which is authentic but what I would want is whether this hadith is a metaphor in general as it can't happen in real with a human to live long enough to leave thousand offspring behind. And if it is true that they must have been far times more than the human species and it would require a huge area to contain them in it as though earth would itself be smaller for them to live by. What do you say? Is this hadith is a metaphor or literal?"...and a man amongst them will not die until he leaves behind one thousand of his offspring..."

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

The Hadith which states that ‘a man amongst Gog and Magog will not die until he leaves behind him one thousand of his offspring’ was reported by an-Nasaa’i in as-Sunnan al-Kubra, and by al-Haakim in al-Mustadrak.

Al-Haakim classified it as Saheeh (authentic), and ath-Thahabi agreed with him in this regard.

However, al-Albaani ruled in As-Silsilah adh-Da'eefah (no. 3209) that its chain of narrators is weak because one of its narrators is unknown.

After Ath-Thahabi classified this Hadeeth as-Saheeh, he commented saying that he failed to take into consideration that Wahb ibn Jaabir was unknown, and he ruled that this narrator is unknown.

This hadeeth was also reported by at-Tayaalisi, and al-Albaani also said in al-Silsilah ad-Da'eefah (no. 4142) that it is objectionable, and he provided three reasons for its weakness.

There is also another Hadeeth that reads: “A man amongst them does not die until he sees a thousand males in front of him from his offspring, each of whom has taken up arms.” Ibn 'Uday reported it in al-Kaamil, and al-Albaani said about it: “It is fabricated.”

To conclude, this Hadeeth is not authentic as it appears.

Allah knows best.