What is the ruling on saying: "(May God) spare you his evil" and "for my sake"?

The phrase "May Allah suffice you against his evil" ("yakfīka sharruhu") can be interpreted as a supplication, meaning "May Allah protect you from his evil." This is permissible because Allah is sufficient for His servants, and He has encouraged us to seek His protection from evils, as stated in the verse: "Say, 'I seek refuge in the Lord of daybreak from the evil of that which He created...'" (Qur’an 113:1-2). It can also be interpreted as an informative statement, meaning that the person will protect you from his evil, which is also acceptable.