Allah Almighty says:

Behold! Verily on the friends of Allah there is no fear, nor shall they grieve; those who believe and guard against evil. For them are glad tidings, in the life of this world and in the Hereafter... [Yunus 10:62-64]

The Messenger of Allah (ﷺ) explained the glad tidings of the life of this world to be dreams. He said it is:

the good dream that a Muslim sees or is seen for him.

The world of dreams is an amazing and intriguing one. The early scholar of Islam Ibn Qutaybah says:

There is nothing that people deal with from the different sciences that is more obscure, delicate, exalted, noble, difficult, and problematic than dreams, because they are a type of revelation and a kind of prophethood.