Our lifespan and relationship to Shakyamuni Buddha is what ties us to this Saha world

"But the great bodhisattvas as numerous as the dust particles of a thousand worlds who emerged from the earth have first of all lived in this sahā world for an incalculably long period of time; second, they have been disciples of Shakyamuni Buddha since the far distant past, when he first set his mind on and attained enlightenment; and third, these bodhisattvas were the first persons in the sahā world to receive the seed of Buddhahood from the Buddha. Therefore, in terms of the bonds of karma from the past that tie them to the sahā world, they surpass the other great bodhisattvas."