Rashi on Exodus 28:32/רש"י על שמות כ״ח:ל״ב

1והיה פי ראשו AND THE HOLE IN THE HEAD OF IT SHALL BE — the hole of the Robe which is at its top — that is, the opening which serves as a receptacle for the neck,

2בתוכו IN THE MIDST THEREOF — Understand this as the Targum renders it: כפיל לגויה “turned in towards the inside” — the turn-in shall serve as its seam. It was weaver’s work (woven as such with the Robe) and not made with a needle.

3כפי תחרא AS IT WERE THE HOLE OF A HABERGEON — This informs us that their habergeons had the neck-opening turned in.

4לא יקרע means SO THAT IT BE NOT RENT — Indeed, whoever rends it, transgresses thereby a negative commandment because this is among the number of the negative commands contained in the Torah. The same is the case with (v. 28) “that the breast-plate be not loosened”, and similarly, (Exodus 25:15) “they shall not depart from it”, which is said of the staves of the ark (Yoma 72a).