Vijnana Bhairava Tantra
यदवेद्यं यदग्राह्यं यच्छून्यं यदभावगम् । तत्सर्व भैरवं भाव्यं तदन्ते बोधसम्भवः ॥ १२७ ॥
By contemplating on bhairava as all that which is void and cannot be known, grasped or imagined, at the end realization takes place.
english translation
yadavedyaM yadagrAhyaM yacchUnyaM yadabhAvagam । tatsarva bhairavaM bhAvyaM tadante bodhasambhavaH ॥ 127 ॥
hk transliteration by Sanscript