Ravens are an example of God's gracious provision for all His creatures in Psalm 147:9 and Job 38:41. (In the New Testament as well, ravens are used by Jesus as an illustration of God's provision in Luke 12:24.)
Luke 12:24 and Psalm 137 offer a common adage, “Consider the ravens: They do not sow or reap, they have no storeroom or barn; yet God feeds them. And how much more valuable you are than birds!”