Body as Instrument, Not End
Deha-yātrā ('the journey of the body' — maintaining the body's existence) refers to the prapanna's approach to physical sustenance. Having surrendered fully, the prapanna no longer maintains the body for personal pleasure or comfort, but solely as the instrument through which kaiṅkarya (service to Bhagavān and His devotees) can be performed in the present life.
Piḷḷai Lokācārya's Teaching
In Śrīvacana Bhūṣaṇam, Piḷḷai Lokācārya teaches that the prapanna eats only to sustain the body for the Lord's service — 'deha-dhāraṇa' — just as a king's servant eats only to be fit for the king's service, not for personal enjoyment. This transforms even the most mundane acts of bodily maintenance into acts of devotion.
Practical Application
Deha-yātrā is the practical expression of the prapanna's reorientation: the body that was once maintained for one's own enjoyment is now understood as Bhagavān's property, to be kept in working order for His use. Even illness and aging are accepted as the Lord's will, without seeking extraordinary remedies beyond what sustains kaiṅkarya.