Appears 4 times in the Quran. (Root: صدر)
  1. A Book revealed to you-- so let there be no straitness in your breast on account of it-- that you may warn thereby, and a reminder close to the believers.

  2. Then, it may be that you will give up part of what is revealed to you and your breast will become straitened by it because they say: Why has not a treasure been sent down upon him or an angel come with him? You are only a warner; and Allah is custodian over all things.

  3. And surely We know that your breast straitens at what they say;

  4. Have We not expanded for you your breast,