Seeking Knowledge or Giving Da'wah?

Shaykh Saalih bin ‘Uthaymeen (rahimahullah) was asked:
Which of the two is preferable: Devoting oneself in calling to Allah Azza Wajel or devoting oneself in seeking knowledge?
The Shaykh replied: Seeking knowledge is better and is given priority, and it is possible for the student of knowledge that he calls to Allaah whilst seeking knowledge. And it is not possible that he calls to Allah whilst being upon other than knowledge,
Allah says,
Say (O Muhammad ): “This is my way; I invite unto Allah (i.e. to the Oneness of Allah – Islamic Monotheism) with sure knowledge” (Surah Yusuf/108).
Therefore how can dawah to Allaah exist without knowledge? And no-one has ever given da’wah without knowledge, and whosever gives da’wah without knowledge is not successful.
Taken from the Fataawa of the Shaykh, Kitab ul-‘ilm, Page 145
Translated by Sa’d Bin Musa As-Soomalee