Bismillaah Al-Hamdulillaah wa salatu wa salaamu ‘ala rasulullaah
However, when the person says, ‘I take refuge (a’oodhu) with Allaah,’ he is actually implementing and realizing what he seeks, because he sought refuge and protection with Allaah. There is a clear difference between actually taking refuge and seeking refuge. Therefore, because the one who is taking refuge is actually recoursing to Allaah, and holding firmly to Him, he says the verb that denotes this rather than saying the verb that denotes that he only seeks this.
The opposite is true for the saying, ‘Astaghfirullaah’ (I seek the forgiveness of Allaah), for in this case the person is asking Allaah to forgive him. Therefore, when he says, ‘Astaghfirullaah,’ he is implementing what he desires because the meaning of this statement is, ‘I ask Allaah that He forgive me.’
This then is the best way of seeking refuge, and it was for this reason that the Prophet (salallaahu ‘alayhi wa sallam) used to say: “I take refuge with Allaah from the accursed Shaytaan,” and “I take refuge with Allaah’s perfect words,” and ‘”I take refuge with the Might and Power of Allaah,’ saying, ‘a’oodhu’ rather than ‘asta’idhu.’ Indeed, this is what Allaah taught him to say with His words:
Say: “I take refuge with (Allaah) the Lord of mankind, (An-Nas, ayah 1)
(Ibnul al-Qayyim, Bada`i al-Fawa`id, vol. 1, pg. 439-441; Tafsir al-Qayyim, pp. 538-541)