The Quran

187

وَإِذ أَخَذَ اللَّهُ ميثاقَ الَّذينَ أوتُوا الكِتابَ لَتُبَيِّنُنَّهُ لِلنّاسِ وَلا تَكتُمونَهُ فَنَبَذوهُ وَراءَ ظُهورِهِم وَاشتَرَوا بِهِ ثَمَنًا قَليلًا ۖ فَبِئسَ ما يَشتَرونَ

Muhammad Asad

AND LO, God accepted a solemn pledge from those who were granted earlier revelation [when He bade them]: "Make it known unto mankind, and do not conceal it!"¹ But they cast this [pledge] behind their backs, and bartered it away for a trifling gain: and how evil was their bargain!²

This connects with verses 183-184, where the Jews are spoken of as refusing to accept the message of the Qur'an. The implication of verse 187 above is that the advent of the Prophet Muhammad was predicted in both the Old and New Testaments, and that the followers of the Bible had been called upon to spread this prophecy and not - as they actually have done - to suppress it.
Lit., "that which they are buying" - an allusion to the belief of the Jews that they are "God's chosen people", and to the conviction of the Christians that their belief in Jesus' "vicarious atonement" automatically assures to them salvation: the "bargain" being, in both cases, an illusion of immunity in the life to come.