מלכים ב, פרק ט״ז, פסוק ח׳

Appealing to foreign kings for assistance is rarely effective on its own; such requests must be backed by a tangible payment. Recognizing this reality, Ahaz gathered the silver and gold located directly inside the House of God [מצודת ציון].

These funds were taken from the Temple treasury, which practically functioned as the national treasury at the time [ביאור שטיינזלץ]. Combining this sacred wealth with the riches stored in his own royal palace, Ahaz sent the entire collection to the king of Assyria as a bribe to secure his help.