Protect you from whom?
If, say, he were to cut down a tree and it landed on Mr. X, no agreement between the two of you will take away Mr. X's legal right to sue.
What you probably want is an indemnity: he agrees to indemnify you in the event Mr. X sues you. But if he doesn't have insurance, that may be of limited usefulness. How is he going to indemnify you for the hundreds of thousands of dollars Mr. X might receive in judgment against you for medical bills, pain and suffering, etc.?
