Psalm 41:9

Yea, mine own familiar friend
Or, "the man of my peace" {z}; who did live peaceably with him, and ought always to have done so; whom he treated as his friend, as the rest of the apostles; calling him to that high office, and ordaining him to it, and qualifying him for it; and whom he called by the name of friend, when he came to betray him; Judas is meant;

in whom I trusted;
with the bag and the money in it, both for the sustenance of his own family, the apostles, and for the relief of the poor, ( John 12:6 ) ( 13:29 ) ;

which did eat of my bread;
of his bread in common with the rest of the apostles; and who was eating with him when he gave the sign who should betray him; and who seems to have eaten of the bread in the Lord's supper: even this same person

hath lifted up his heel against me;
by supplanting him, dealing hypocritically with him, and betraying him into the hands of his enemies: the metaphor is either taken from an unruly horse throwing his rider, and then ungenerously spurning at him, and trampling on him; or from wrestlers, who seek to supplant and trip up each other's heels; which shows the ingratitude, baseness, and treachery of Judas; see ( John 13:18 ) .