Sirach 12:10
Ben Sira, Ecclesiasticus8 A friend is not known in prosperity, nor is an enemy hidden in adversity. 9 One's enemies are friendly when one prospers, but in adversity even one's friend disappears. 10 Never trust your enemy, for like corrosion in copper, so is his wickedness. 11 Even if he humbles himself and walks bowed down, take care to be on your guard against him. Be to him like one who polishes a mirror, to be sure it does not become completely tarnished. 12 Do not put him next to you, or he may overthrow you and take your place. Do not let him sit at your right hand, or else he may try to take your own seat, and at last you will realize the truth of my words, and be stung by what I have said.
James 5:3
1 Come now, you rich! Weep and cry aloud over the miseries that are coming on you. 2 Your riches have rotted and your clothing has become moth-eaten. 3 Your gold and silver have rusted and their rust will be a witness against you. It will consume your flesh like fire. It is in the last days that you have hoarded treasure! 4 Look, the pay you have held back from the workers who mowed your fields cries out against you, and the cries of the reapers have reached the ears of the Lord of Heaven’s Armies. 5 You have lived indulgently and luxuriously on the earth. You have fattened your hearts in a day of slaughter.
Notes and References
"... Much evidence suggests that James is adapting his language from a specific Jewish tradition (Sirach 12:10–11; 29:8–12) that similarly condemns the static hoarding of wealth. The high likelihood that James is interacting with Sirach is based on the following evidence: (1) the verb “to corrode” occurs in the Greek Bible only in Sirach 12:10–11 and James 5:3. (2) The noun “rust” is rare, occurring in only two other contexts in the Greek Bible: Epistle of Jeremiah 1:10, 23 and Ezekiel 24:6–12. The verbal form “to rust” occurs only in Sirach 12:10; 29:10. Thus, the rare word group occurs in only five contexts total in the Greek Bible, with three being James 5:3, Sirach 12:10, and Sirach 29:10. (3) Like James 5, Sirach 12 and 29 teach about the use of wealth. (4) The terms silver, gold, and treasure all occur in James 5:2–3 and Sirach 29:10–11. This linguistic and thematic evidence suggests that James is interacting with Sirach’s teaching on wealth and poverty ..."
Scacewater, Todd The Dynamic and Righteous Use of Wealth in James 5:1-6 (pp. 227-242) Journal of Markets & Morality Volume 20, Number 2, 2017