There is optionally the substitution of ā in the room of the diphthong of the root bhī 'to fear' in the causative, when the fear is produced directly through the agent of the causative.,
The words णौ and विभाषा are understood here. The word हेतु in the sutra is the technical हेतु meaning स्वतन्त्रस्य प्रयोजक 1.4.54 and 1.4.55. When the Hetu Agent himself is directly the cause of the fear, that fear is called the हेतुभय \the fear caused by the Hetu\. Thus मुण्डो भापयते 7.3.36 or भीषयते 7.3.40. So also जटिलो भापयते or भीषयते ॥ This root takes the affixes of the Atmanepada, by 1.3.68; and the augment ष is added by 7.3.40, which does not come when there is आ substitution, for the भी in 7.3.40 is equal to भ् + ई i.e. भी ending in ई; and means भी ending in ई takes the augment ष ॥
Why do we say 'when the agent of the causative is the producer of the fear'? Observe कुञ्चिकयैनं भाययति देवदत्तः ॥ Here the fear is produced from the कुञ्चिका and not from Devadatta the Agent.,