פירוש על עבודה זרה 48:2

Saul, when he conquers the Amalekites, offers up the best of their animals as sacrifices (instead of doing what he is supposed to do and killing everyone and everything). Again, animals brought from non-Jews are acceptable. The answer is that Saul did not actually sacrifice these animals. He sold them and then used the money to buy sacrifices. But this is strange—if he’s just selling the animals, why does it matter that they are the best? He could sell any of them. The answer is that the best animals are most easily sold.