Lech Lecah: a different type of nisayon
His answer is that the test here is the challenge to do the action because of the command in spite of the tangible benefit it will bring. In that way, it is like the command to eat on the 9th of Tishrei, which is said to be as great as fasting on Yom Kippur. It is so when one's motivations are pure -- fulfilling the command even when there is personal pleasure involved.
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