the.com/salt of the earth

means Used to describe someone fundamentally decent, honest, and unpretentious — the reliable, good-hearted type you'd trust without a second thought.

from Straight from the Bible's Sermon on the Mount, where Jesus tells his followers 'Ye are the salt of the earth' — meaning they give the world its savor and keep it from spoiling. In the ancient world, salt was precious: it preserved food, flavored it, and was even used as currency and wages (the word 'salary' comes from the Latin for salt). So calling someone 'salt of the earth' wasn't a throwaway compliment — it meant they were essential, something that kept the whole enterprise from going rotten.