Brahma Sutras
ॐ अरूपवदेव हि तत्प्रधानत्वात् ॐ ॥ ३-२-१४॥
Brahman is only formless to be sure, for that is the dominant note (of the Upanishadic teaching).
english translation
OM arUpavadeva hi tatpradhAnatvAt OM ॥ 3-2-14॥
hk transliteration by Sanscript