When a person becomes disturbed in his heart by seeing lightning in the sky, by seeing a ferocious animal or by hearing a tumultuous sound, his state of mind is called apprehensive. In such a state of apprehension, one tries to take shelter of something which provides safety. There may be standing of the hairs on the body, trembling of the body and sometimes the committing of mistakes. And sometimes the body may become stunned.
In the Padyāvalī there is the following statement: "My dear friend, Kṛṣṇa's residence in the demoniac circle at Mathurā, under the supremacy of the king of demons, Kaṁsa, is causing me much worry." This is one instance of apprehending some danger to Kṛṣṇa in ecstatic love for Him.
When Vṛṣāsura appeared in Vṛndāvana as a bull, all of the gopīs became greatly affected with fear. Being perturbed in that way, they began to embrace the tamāla trees. This is an instance of fear caused by a ferocious animal and of the search for shelter while remembering Kṛṣṇa in ecstatic love. Upon hearing the jackals crying in the forest of Vṛndāvana, mother Yaśodā sometimes became very careful about keeping Kṛṣṇa under her vigilance, fearing that Kṛṣṇa might be attacked by them. This is an instance of ecstatic love for Kṛṣṇa in fear caused by a tumultuous sound. This kind of fear is a little different from being actually afraid. When one is afraid of something, he can still think of past and future. But when there is this kind of ecstatic apprehension, there is no scope for such thinking.