"Our Lord, make us not a trial" - meaning a tribulation - "for those who have disbelieved" - the verse. That is: do not let the polytheists overcome us, for then they would say: 'If these people were following the true religion, we would not have overcome them,' and thus they would be tempted/tested by us.

Tafsir of Surat al-Mumtahanah from verse 6 to verse 9.