SB 1.6.9

ekadā nirgatāṁ gehād
 duhantīṁ niśi gāṁ pathi
sarpo ’daśat padā spṛṣṭaḥ
 kṛpaṇāṁ kāla-coditaḥ
Synonyms: 
ekadā — once upon a time; nirgatām — having gone away; gehāt — from home; duhantīm — for milking; niśi — at night; gām — the cow; pathi — on the path; sarpaḥ — snake; adaśat — bitten; padā — on the leg; spṛṣṭaḥ — thus struck; kṛpaṇām — the poor woman; kāla-coditaḥ — influenced by supreme time.
Translation: 
Once upon a time, my poor mother, when going out one night to milk a cow, was bitten on the leg by a serpent, influenced by supreme time.
Purport: 

That is the way of dragging a sincere soul nearer to God. The poor boy was being looked after only by his affectionate mother, and yet the mother was taken from the world by the supreme will in order to put him completely at the mercy of the Lord.