John Gill Commentary Exodus 29:17

"And thou shalt cut the ram into its pieces, and wash its inwards, and its legs, and put them with its pieces, and with its head." — Exodus 29:17 (ASV)

And thou shalt cut the ram in pieces
For the better convenience of laying it upon the wood on the altar, that it might be burnt; for it was to be a whole burnt offering:

and wash the inwards of him, and his legs ;
denoting the purity of the sacrifice of Christ, and that when his people give up themselves to God as a whole burnt offering, in the flames of love and zeal, their affections should be pure and sincere:

and put [them] unto his pieces, and unto his head ;
lay them together, so that they might be entirely consumed at once; signifying that Christ was both in soul and body an offering and a sacrifice of a sweet smelling savour to God; zeal for the honour of whose house, and the glory of his name, ate him up, as well as the fire of divine wrath; and so our whole souls, bodies and spirits, should be presented to the Lord as a holy, living, and acceptable sacrifice to him, which is more strongly suggested in the next verse.