The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
24. This follows also from the connexion (of the stories with the vidyâs) in one coherent whole.
And as thus the stories do not subserve the pâriplava it
is appropriate to assume that they are meant to bring nearer to our understanding the approximate vidyâs with which they are seen to form connected wholes; for they serve to render the latter more acceptable and facilitate their comprehension.
In the Maitreyî-brâhmana we see that the story forms a whole with the vidyâ beginning, 'The Self indeed is to be seen,' &c.; in the account of Pratardana with the vidyâ, 'I am prâna, the conscious Self;' in the legend of Gânasruti with the vidyâ, 'Air indeed is the end of all.' The case of all these stories is analogous to that of stories met with in scriptural texts referring to works, whose purpose is the glorification of injunctions standing in proximity; as e.g. 'He cut out his own omentum.'--The stories under discussion therefore do not subserve the pâriplava.