The 2 Kings passage (and its parallel in Isaiah 37:30) refers to a sabbath ("shmita") year followed by a jubilee ("yovel") year. The text says that in the first year the people were to eat "what grows of itself", which is expressed by one word in the Hebrew, "saphiah" (ספיח). In Leviticus 25:5, the reaping of the "saphiah" is forbidden for a Sabbath year, explained by rabbinic commentary to mean the prohibition of reaping in the ordinary way (with, for example, a sickle), but permitted to be plucked in a limited way by one's own hands for one's immediate needs during the Sabbath year.