His People are those He did Federally represent, which also because of it, their sins were legally charged to Him, and this is most indicated here Heb 2:16-17
16 For verily he took not on him the nature of angels; but he took on him the seed of Abraham.
17 Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.
Because He was the Seed of Abraham Gal 3:16, it was appropriate that the Seed of Abraham sins was charged upon Him, for He represented that People, and all who become Believers and belong to Him, are the Seed of Abraham Gal 3:29
29 And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise ! 5
16 For verily he took not on him the nature of angels; but he took on him the seed of Abraham.
17 Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.
Because He was the Seed of Abraham Gal 3:16, it was appropriate that the Seed of Abraham sins was charged upon Him, for He represented that People, and all who become Believers and belong to Him, are the Seed of Abraham Gal 3:29
29 And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise ! 5