佛頂尊勝陀羅尼經教跡義記 2.48

2.48

唐云堅住持壽命。解曰：諸佛既以攝受壽命，即是住持。又解：報力住持唯是第八，諸佛攝受乃得延齡。又解：持此真言延命增壽，不被諸魔奪其命根，如善住天子受持之力，其命轉增遠記菩提成無上果。

In Chinese it means: "Firmly preserve and uphold lifespan." The explanation states: Since the Buddhas have gathered and received the lifespan, this is "preserving and upholding." Another explanation: Preserving and upholding the power of retribution pertains solely to the eighth [consciousness]; it is through the Buddhas' gathering and receiving that life is extended. Another explanation: Holding this mantra prolongs life and increases lifespan, preventing the māras from snatching away one's life-faculty, just as by the power of receiving and upholding it, Devaputra Susthita had his life further increased, received the distant prophecy (vyākaraṇa) of bodhi, and achieved the unexcelled fruit.