Midrasch zu Wajikra 26:34

2) (Vayikra 26:34) "Then shall the land requite its Sabbaths": I told you to sow six (years) and to leave one unsown for Me, so that you should know that the land is Mine. But you did not do so — Arise and be exiled from it, and it will lie waste of itself, all the shemitah years that it owes Me. As it is written: "Then shall the land requite its Sabbaths. All the days of its (unrequited) Sabbaths … shall it rest."

This is what God said to Israel: My children what do I seek from you? I seek no more than that you love one another, and honor one another, and that you have awe for one another