Sirach (Ecclesiasticus) — Chapter 12

If thou do good, know to whom thou dost it; and there shall be much thanks for thy good deeds. Discernment in beneficence: know before you give. Lapide notes the distinction between universal charity (which wills good to all) and discriminate almsgiving (which directs material benefits to those who will use them well).

For the Most High hateth sinners, and will repay vengeance to the ungodly. God's hatred of sin is the theological basis for limiting beneficence to the impious. Lapide carefully distinguishes God's love for sinners as persons from His hatred of sin and His just wrath against the impenitent.

A friend shall not be known in prosperity, and an enemy shall not be hidden in adversity. Prosperity conceals the false friend; adversity reveals the true enemy. Lapide treats this as one of the deepest maxims of human experience, supported by Scripture and classical philosophy.

Never trust thy enemy; for as iron rusteth, so is his wickedness. The enmity of the wicked is permanent, like the rust of iron. Lapide's extended simile: as iron inevitably rusts when conditions allow, so the enemy inevitably returns to his malice when opportunity presents itself.

He will remain with thee but for a time, and if thou begin to fall, he will not bear it. The false friend's devotion is entirely conditional on personal advantage. Lapide contrasts this with true friendship: the genuine friend is most constant precisely in the time of greatest adversity.

In his lips he will be sweet, and in his heart he will plan to overthrow thee into a pit. The enemy's sweet lips conceal a predatory heart. Lapide treats this as a psychological portrait of the hypocrite and traitor, warning that external sweetness must always be evaluated against interior consistency.