[3:187] GOD took a covenant from those who received the scripture: “You shall proclaim it to the people, and never conceal it.” But they disregarded it behind their backs, and traded it away for a cheap price. What a miserable trade.
What does 3:187 mean when it says “what a miserable trade”?
People who sell out the hereafter for this life when this life is an illusion. They are willing to disregard their morality for a material gain.
Righteous Jews and Christians
[3:199] Surely, some followers of the previous scriptures do believe in GOD, and in what was revealed to you, and in what was revealed to them. They reverence GOD, and they never trade away GOD’s revelations for a cheap price. These will receive their recompense from their Lord. GOD is the most efficient in reckoning.
Additionally when you see what they give up for the quick gain you realize just how lousy of a trade it really was:
[3:91] Those who disbelieve and die as disbelievers, an earthful of gold will not be accepted from any of them, even if such a ransom were possible. They have incurred painful retribution; they will have no helpers.
The Cost of Disbelief
[5:36] Certainly, those who disbelieved, if they possessed everything on earth, even twice as much, and offered it as ransom to spare them the retribution on the Day of Resurrection, it would not be accepted from them; they have incurred a painful retribution.