Zohar on Tehillim 31 - Cherubim in the Aron Kodesh
Tehillim 31:20
- "Mah rav tuvkha asher tzafanta lire'ekha, pa'alta lachosim bakh neged benei adam"-
(how abundant is Your goodness, O G-d, which You have stored up for those who fear You, which You have accomplished for those who trust in You).
When the Aron Kodesh is opened and the Torah is taken out, the Cherubim open their mouths and spread their wings. They sanctify that entrance with the Supernal Light, and when the Torah scroll is unrolled, the Cherubim say: "How abundant is Your goodness, O G-d, which You have stored up."
Then they close the entrances, and the Torah scroll is rolled up.
(Zohar on Shelach, Baal HaSulam, Nisanzon)