Charles Ellicott Commentary Psalms 41:9

"Yea, mine own familiar friend, in whom I trusted, Who did eat of my bread, Hath lifted up his heel against me." — Psalms 41:9 (ASV)

Has lifted up his heel. —See margin. The meaning is, possibly, kicked violently at me. But Böttcher’s conjecture is valuable, “has magnified his fraud against me,” which is supported by the Septuagint and Vulgate, “has magnified his supplanting of me.” (For the quotation of this verse in John 13:18, see New Testament Commentary.)

The rights of Eastern hospitality must be remembered, to bring out all the blackness of the treachery here described. The expressive Hebrew idiom, “man of my peace,” is retained in the margin. Possibly (see Note, Obadiah 1:7) the second clause recalls another idiom, “man of my bread.”