I would like to know what Allaah as first have created in the whole universe.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Imaam Al-Bukhari reported that people from Yemen came to the Prophet and told him: "We came to you to increase our religious knowledge and to ask you about the first thing that Allaah has created." So the Prophet told them: "First there was Allaah and there was nothing before Him and His Throne was upon water, then He created the heavens and the earth and recorded in the Preserved Book everything that will happen…." [Ahmad, Ibn Hibbaan and others] The saying of the Prophet : "…and His Throne was upon water" is an evidence that water and the Throne were the beginning of this world as they were created before the heavens and the Earth, and at that time there was nothing under the Throne except water. As regards the narration: "The first thing which Allaah had created was the Pen," [At-Tirmithi and others] means that when Allaah created the pen, He ordered it to write, and this is after Allaah created the Throne and water.

Allaah knows best.