وَلِيُمَحِّصَ اللّهُ الَّذِينَ آمَنُواْ وَيَمْحَقَ الْكَافِرِينَ
[3:141]
And that He may purge those who believe and deprive the unbelievers of blessings.
Allah's object also is to purge those that are true in Faith and to deprive of blessing Those that resist Faith.
And that Allah may prove those who believe, and may blight the disbelievers.