What do we learn from "Acharav Ya'ir Nasiv"?
'Rashi': When it swims, the way of the Tehom illuminates, for while it was swimming, there was no water there.
Ibn Ezra: It makes a path in the sea after it and illuminates, i.e. makes it visible 1 .
Malbim: The verse depicts that the Tehom thinks that even if it would boil the deep water via its great fire, this would not kill the Livyasan. Rather, from the darkness of the sea, there would be a path of light in back of it.
How does it considered the Tehom like old age?
'Rashi': Compared to it, the Tehom is weak like an elder.
Ibn Ezra: An elder's hair is white. This repeats the Reisha (NOTE: it makes the water white, i.e. foam - PF).
Malbim: Even if the Tehom would boil the deep water, and kill everything [else] in the sea, the Livyasan would live until old age.
