His garments - The plural here is used to denote the outer garment. It was made, commonly, so as to be easily thrown on or off, and when they labored or walked it was girded about the loins. See the notes at Matthew 5:40.
Four parts - It seems, from this, that there were four soldiers employed as his executioners.
His coat - His under garment, called the tunic.
Was without seam - Josephus (Antiq., b. 3 chapter 8, Section 4) says of the garment or coat of the high priest that “this vesture was not composed of two pieces, nor was it sewed together upon the shoulders and the sides; but it was one long vestment, so woven as to have an aperture for the neck. It was also parted where the hands were to come out.” It seems that the Lord Jesus, the great High Priest of his people, had also a coat made in a similar manner. Compare Exodus 39:22.