Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · War Astrology: Yogas, Nakshatras
युद्धजयार्णवः (योगाः नक्षत्राणि)
क्रूरा शक्तिरीबीजः स्याद्धरवीजोऽग्निरूपवान् ।विद्या समाना गान्धारी शक्तिश्च दहनी स्मृता ॥
In the full Agni Purana this is chapter 124, verse 12.
Cruel Shakti has the long i as her seed. The Hara seed has the form of fire. Vidya, Samana, Gandhari and the power called Dahani are remembered.
Simple meaning: Powers and seed letters are named, including cruel Shakti and a fire-like seed.
ए शान्तिर्वार्युपस्पर्शो यश्चोदानश्चला क्रिया ।
The vowel e goes with air and touch. Om goes with space and sound.
पञ्च वर्गाः स्वरा जाताः कुजज्ञगुरुभार्गवाः ।
The five letter groups come from the vowels and match Mars, Mercury, Jupiter, Venus and Saturn in order.
एतन्मूलमतः सर्वं ज्ञायते सचराचरम् ।
From this root all is known. Next the seat of knowledge is told, and Om is called Shiva.