The word “unseen” in the Qur’an means everything beyond one's perceptions and knowledge, everything concealed from the eyes. Knowledge of the unseen is Allah’s alone. And Allah informs us that He grants this knowledge only to those He wills. The Prophet Muhammad (saas) stated that it was Allah alone Who knew the “unseen":

Say: “Allah knows best how long they stayed. His are the secrets of the heavens and the Earth. How perfectly He sees, how well He hears! Man has no protector apart from Him. Nor does He share His rule with anyone.” (Surat al-Kahf, 26)

Say: “No one in the heavens and on Earth knows the Unseen except Allah.” Men shall never be aware of when they will be raised to life. (Surat an-Naml, 65)

Say: “My Lord hurls forth the Truth—the Knower of all unseen things.” (Surah Saba’, 48)