al-Iṣtirāʾ is interpreted in three ways:
1. Iṣtirāʾ is used in the sense of choosing or preferring; as in the following verses:
Thus, they {that is, the leaders among the Jews} have iṣtirāʾ dalāla (chosen misguidance) in exchange for hudā (guidance) {that is, they have preferred to deny Muḥammad, who was sent to be believed in}. (al-Baqara 2:16 and 2:175)
Those who conceal something from the Book which Allah has sent down and iṣtirāʾ it for a small price {that is, who choose to deny Muḥammad in exchange for a trivial worldly gain}... (al-Baqara 2:174)
And among the people is he who iṣtirāʾ lahw al-ḥadīth {that is, who prefers vain discourse over the Qur'an: instead of choosing the Qur'an, they choose idle talk}. (Luqmān 31:6)
2. The term al-Iṣtirāʾ is used in the sense of buying; as in the following verse:
Indeed, Allah has iṣtirāʾ (purchased) from the believers their lives and their properties in exchange for Paradise {that is, has bought them}. (al-Tawba 9:111)
3. The term ishtaraw is used in the sense of selling; as in the following verse:
How wretched is that for which they ishtaraw (sold) themselves; to disbelieve in what Allah has sent down... (al-Baqara 2:90)
There is no other example of this (that is, the word ishtarāʾ being used in the sense of "to sell" does not occur in any other verse).