The property of widows or of all the faithful, that has been entrusted to the Church, ought to be defended though it brings danger to oneself. This is illustrated by the example of Onias the priest, and of Ambrose, bishop of Ticinum.
144. Great care must be taken that the property entrusted by widows remains inviolate. It should be guarded without causing complaint, not only if it belongs to widows, but to any one at all. For good faith must be shown to all, though the cause of the widow and orphans comes first.
145. So everything entrusted to the temple was preserved in the name of the widows alone, as we read in the book of the Maccabees. For when information was given of the money, which Simon treacherously had told King Antiochus could be found in large quantities in the temple at Jerusalem, Heliodorus was sent to look into the matter. He came to the temple, and made known to the high priest his hateful information and the reason of his coming.
146. Then the priest said that only means for the maintenance of the widows and orphans was laid up there. And when Heliodorus would have gone to seize it, and to claim it on the king's behalf, the, priests cast themselves before the altar, after putting on their priestly robes, and with tears called on the living God Who had given them the law concerning trust-money to show Himself as guardian of His own commands. The changed look and colour of the high priest showed what grief of soul and anxiety and tension of mind were his. All wept, for the spot would fall into contempt, if not even in the temple of God safe and faithful guardianship could be preserved. Women with breasts girded, and virgins who usually were shut in, knocked at the doors. Some ran to the walls, others looked out of the windows, all raised their hands to heaven in prayer that God would stand by His laws.
147. But Heliodorus, undeterred by this, was eager to carry out his intention, and had already surrounded the treasury with his followers, when suddenly there appeared to him a dreadful horseman all glorious in golden armour, his horse also being adorned with costly ornaments. Two other youths also appeared in glorious might and wondrous beauty, in splendour and glory and beauteous array. They stood round him, and on either side beat the sacrilegious wretch, and gave him stroke after stroke without intermission. What more need I say? Shut in by darkness he fell to the ground, and lay there nearly dead with fear at this plain proof of divine power, nor had he any hope of safety left within him. Joy returned to those who were in fear, fear fell on those who were so proud before. And some of the friends of Heliodorus in their trouble besought Onias, asking life for him, since he was almost at his last breath.
148. When, therefore, the high priest asked for this, the same youths again appeared to Heliodorus, clad in the same garments, and said to him: Give thanks to Onias the high priest, for whose sake your life is granted you. But do thou, having experienced the scourge of God, go and tell your friends how much you have learned of the sanctity of the temple and the power of God. With these words they passed out of sight. Heliodorus then, his life having come back to him, offered a sacrifice to the Lord, gave thanks to the priest Onias, and returned with his army to the king, saying: “If you have an enemy or one who is plotting against your power, send him there and you will receive him back well scourged.”
149. Therefore, my sons, good faith must be preserved in the case of trust-money, and care, too, must be shown. Your service will glow the brighter if the oppression of a powerful man, which some widow or orphan cannot withstand, is checked by the assistance of the Church, and if you show that the command of the Lord has more weight with you than the favour of the rich.
150. You also remember how often we entered on a contest against the royal attacks, on behalf of the trust-money belonging to widows, yea, and to others as well. You and I shared this in common. I will also mention the late case of the Church at Ticinum, which was in danger of losing the widow's trust-money that it had received. For when he who wanted to claim it on some imperial rescript demanded it, the clergy did not maintain their rights. For they themselves, having once been called to office and sent to intervene, now supposed that they could not oppose the emperor's orders. The plain words of the rescript were read, the orders of the chief officer of the court were there, he who was to act in the matter was at hand. What more was to be said? It was handed over.
151. However, after taking counsel with me, the holy bishop took possession of the rooms to which he knew that the widow's property had been carried. As it could not be carried away, it was all set down in writing. Later on it was again demanded on proof of the document. The emperor repeated the order, and would meet us himself in his own person. We refused. And when the force of the divine law, and a long list of passages and the danger of Heliodorus was explained, at length the emperor became reasonable. Afterwards, again, an attempt was made to seize it, but the good bishop anticipated the attempt and restored to the widow all he had received. So faith was preserved, but the oppression was no longer a cause for fear; for now it is the matter itself, not good faith, that is in danger.
Source: On the Duties of the Clergy (New Advent)