مَثَلُ الْعِلْمِ لَا يُنْتَفَعُ بِهِ كَمَثَلِ كَنْزٍ لَا يُنْفَقُ مِنْهُ فِي سَبِيلِ اللَّهِ (Ahmad and Darimi)
Translation: Knowledge that is not benefited from is like a treasure from which nothing is spent in Allah's path.
الْعِلْمِ — knowledge; يُنْتَفَعُ بِهِ — benefit is taken from it; كَنْزٍ — treasure; يُنْفَقُ مِنْهُ — it is spent from.
Brief grammar: Both verbs in لَا يُنْتَفَعُ بِهِ and لَا يُنْفَقُ مِنْهُ are passive: “is benefited from” and “is spent from.” The prefix كَ in كَمَثَلِ marks comparison.
The worth of learning grows when it informs one's own conduct and is accurately shared with others when appropriate.