ذٰلِكَ اَدْنٰٓى اَنْ يَّأْتُوْا بِالشَّهَادَةِ عَلٰى وَجْهِهَآ اَوْ يَخَافُوْٓا اَنْ تُرَدَّ اَيْمَانٌۢ بَعْدَ اَيْمَانِهِمْۗ وَاتَّقُوا اللّٰهَ وَاسْمَعُوْا ۗوَاللّٰهُ لَا يَهْدِى الْقَوْمَ الْفٰسِقِيْنَ ࣖ ( المائدة: ١٠٨ )
Zaalika adnaaa ai yaatoo bishshahaadati 'alaa wajhihaaa aw yakhaafooo an turadda aimaanum ba'da aimaanihim; wattaqul laaha wasma'oo; wallaahu laa yahdil qawmal faasiqeen (al-Māʾidah 5:108)
Sahih International:
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 [i.e., obey Him]; and Allah does not guide the defiantly disobedient people. (Al-Ma'idah [5] : 108)
1 Mufti Taqi Usmani
Thus, it is more likely that the former people (i.e. the executors of the bequest) will bear witness in its proper way, or they will fear that oaths will be taken in rebuttal of their oaths. Fear Allah and listen. Allah does not lead sinning people to the right path.