4471.Ram sing praises to Shiv as upholder of truth, as Sati could not sit next to Shiva, by untruth.

Narrative- Shiva's vow not to entertain Sati as his consort until she changed her body, was upheld until that time that Sati reincarnated as Parvati & performed severe austerities to regain Shiva as her consort & until that time Shiva continuously devoted himself to Rama, so the virtuous Rama recounted Shiva's glory as the embodiment of truthfulness.
One must never deviate from truth, as The Christ put it, broad is the path that leads to destruction, & narrow is the paththat leads to the life. * ( As demonstrated by Sati destroying her body by sacrificial fire to atone for her folly and return in new light, new life, as Parvati ) A rebirth into purity.
As it is, only purity & sincerity can accompany truth. Anytime you deviate from truth it is a lie. So Shiva upheld his vow and Sati had to change her form.