Al-Ma'idah 5:108

ذَٰلِكَ أَدۡنَىٰٓ أَن يَأۡتُواْ بِٱلشَّهَٰدَةِ عَلَىٰ وَجۡهِهَآ أَوۡ يَخَافُوٓاْ أَن تُرَدَّ أَيۡمَٰنُۢ بَعۡدَ أَيۡمَٰنِهِمۡۗ وَٱتَّقُواْ ٱللَّهَ وَٱسۡمَعُواْۗ وَٱللَّهُ لَا يَهۡدِي ٱلۡقَوۡمَ ٱلۡفَٰسِقِينَ 108

That is more likely that they will give testimony according to its [true] objective, or [at least] they would fear that [other] oaths might be taken after their oaths. And fear Allah and listen; and Allah does not guide the defiantly disobedient people