John Gill Commentary Numbers 7:16

"one male of the goats for a sin-offering;" — Numbers 7:16 (ASV)

One kid of the goats for a sin offering .
] Though these offerings of the princes were by way of thanksgiving, and to express their joy and gladness at the erection of the tabernacle, its altars, and the service of it; yet as this might not be without sin, which attends the best and purest performances of men, a sin offering was required, teaching us to look to Christ, who was made an offering for sin, for the taking away the sins of our holy things.