tumi jana, krsna nija-pratijna chadila
bhakta krpa-vase bhismera pratijna rakhila
tumi jana—you know; krsna—Lord Krsna; nija-pratijna—His own promise; chadila—gave up; bhakta krpa-vase—being obliged by the devotional service of a devotee; bhismera—of Grandfather Bhisma; pratijna rakhila—kept the promise.
"You should know that Lord Krsna Himself violated His own promise just to keep the promise of Grandfather Bhisma.
Link to this page: https://prabhupadabooks.com/cc/madhya/16/144