The Quran

141

الَّذينَ يَتَرَبَّصونَ بِكُم فَإِن كانَ لَكُم فَتحٌ مِنَ اللَّهِ قالوا أَلَم نَكُن مَعَكُم وَإِن كانَ لِلكافِرينَ نَصيبٌ قالوا أَلَم نَستَحوِذ عَلَيكُم وَنَمنَعكُم مِنَ المُؤمِنينَ ۚ فَاللَّهُ يَحكُمُ بَينَكُم يَومَ القِيامَةِ ۗ وَلَن يَجعَلَ اللَّهُ لِلكافِرينَ عَلَى المُؤمِنينَ سَبيلًا

Muhammad Asad

who but wait to see what betides you: thus, if triumph comes to you from God, they say, "Were we not on your side?" - whereas if those who deny the truth are in luck, they say [to them], "Have we not earned your affection by defending you against those believers?"¹ But God will judge between you all on the Day of Resurrection; and never will God allow those who deny the truth to harm the believers.²

Lit., "did we not gain mastery over you [i.e., "over your hearts" - cf. Lane II, 664] and defend you against the believers?" The term "believers" has obviously a sarcastic implication here, which justifies the use of the demonstrative pronoun "those" instead of the definite article "the".
This announcement has, of course, a purely spiritual meaning, and does not necessarily apply to the changing fortunes of life - since (as this very verse points out) "those who deny the truth" may on occasion be "in luck", that is to say, may gain temporal supremacy over the believers.