The bin of flour was not used up, nor did the jar of oil run dry, according to the word of the Lord which He spoke by Elijah. 1 Kings 17:16

Ravens feed Elijah and he drinks water from a brook but a lack of rain starts drying up the water. God directs Elijah to go to Zarephath and stay with a widow.
Elijah, an Israelite, is directed to go to a widow, a Gentile. Under the Law this was socially unacceptable. This story sounds similar to the one involving Peter and Cornelius in Acts 10.
As with Peter, Elijah learns a lesson. He’s already been fed by an unclean bird – the raven, which is also socially unacceptable.

His first encounter with the widow finds her gathering sticks to cook the last meal for her and her son.
Elijah insists on a drink of water (in a severe drought) and for her to cook him something first.
Imagine her surprise that an Israelite prophet comes to her with this request. She is a citizen of Sidon, from which Queen Jezebel originates.

God uses this Gentile widow to care for Elijah during the drought and rewards her with a jar of oil that never runs dry and a bin of flour that never goes empty.

Obedience to God leads to provision from God. Sometimes that obedience and provision come in an unusual way or from an unusual source.