Silsilah as-Sahihah 3905 — Who were Tubba and Dhu al-Qarnayn?

Abu Huraira (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "I do not know whether Tubba‘ was accursed or not, and I do not know whether Dhu’l-Qarnayn was a prophet or not, and I also do not know whether the prescribed punishments (for related sins) become an expiation or not."