Arabic clauseMeaning
إِذَا حَدَّثَ كَذَبَWhen he spoke, he lied
إِذَا وَعَدَ أَخْلَفَWhen he promised, he broke it
إِذَا اؤْتُمِنَ خَانَWhen entrusted, he betrayed the trust
حَدَّثَ means spoke; كَذَبَ means lied. وَعَدَ means promised; أَخْلَفَ means broke a promise. اؤْتُمِنَ is passive, indicating that trust was placed in him; خَانَ then describes his betrayal.
Each clause concerns the damage dishonesty does to trust.