SB 10.1.54
sri-vasudeva uvaca
na hy asyas te bhayam saumya
yad vai sahasarira-vak
putran samarpayisye ’sya
yatas te bhayam utthitam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Vasudeva said: O best of the sober, you have nothing to fear from your sister Devaki because of what you have heard from the unseen omen. The cause of death will be her sons. Therefore I promise that when she gives birth to the sons from whom your fear has arisen, I shall deliver them all unto your hands.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Kamsa feared Devaki’s existence because after her eighth pregnancy she would give birth to a son who would kill him. Vasudeva, therefore, to assure his brother-in-law the utmost safety, promised to bring him all the sons. He would not wait for the eighth son, but from the very beginning would deliver to the hands of Kamsa all the sons to which Devaki would give birth. This was the most liberal proposition offered by Vasudeva to Kamsa.