John 13:18-20 I speak not of you all: I know whom I have chosen: but that the scripture may be fulfilled, He that eats bread with me hath lifted up his heel against me. Now I tell you before it come, that, when it is come to pass, you may believe that I am he. Verily, verily, I say unto you, He that receives whomsoever I send receives me; and he that receives me receives him that sent me.
The ‘all’ of verse 18 refers to Judas again (vv. 10-11). Jesus prayed all night for the will of God concerning whom He should choose (Luke 6:12-16) when He chose His disciples. He chose Judas, not as a wicked man, nor that he should become such; but He foresaw that he would not remain true to Him, and would deliver Him into the hands of His enemies and bring ruin upon himself. Jesus even tried to prevent this, but Jesus would not listen.
The 9th Old Testament prophecy in John which is fulfilled. Eating bread with Jesus made the crime of Judas all the more sinful, for in the East it is a custom that eating bread with an enemy makes you friends and rights of hospitality cannot be broken. It seals the bond of mutual friendship, kindness, and protection of each other.
Plenty of facts are mentioned about Judas in the Word: he was an apostle (Matt. 10; Mark 3:13-19); he was filled with the Spirit (Matt. 10:20); he was ordained to teach (Mark 3:13); and ordained to heal (Mark 3:13-14); he was endowed with power (Matt. 10:1-8); a successful teacher and healer (Mark 6:7-13; Luke 9:6,10); he baptized others in water (John 4:1-2); and was a possessor of eternal life (John 17:2 with v12); he was a saved man and had his name in the book of life (Acts 1:20 with Ps. 69:25-28; cp. Luke 10:20 with Mark 6:13); he was a familiar friend of Christ (Ps. 41:9) and trusted by Christ (Psalm 41:9). Since Christ knew what was in men (John 2:25) He knew Judas could be trusted like any saved man until he falls. He was not an enemy of Christ, not one that hated Him, but an equal in grace, a guide, and an acquaintance who counselled and fellowshipped with Him (Ps. 55:12-14). Later, he became a thief (John 12:4-6), an adversary (John 6:70), and unclean (John 13:10-11), and “by transgression fell” like all backsliders (Acts 1:25; Mark 14:21)
‘Lifted up his heel’ A reference to an ill-natured horse that sometimes kicks even the person who feeds and cares for him.