Or if his sin - Rather, And if his sin.
Come to his knowledge - i. e. when he had become conscious of his sin.
A kid of the goats - A shaggy he-goat, in distinction from a smooth-haired he-goat. It was the regular sin-offering at the yearly festivals Leviticus 16:9, Leviticus 16:15; Numbers 28:15, Numbers 28:22, Numbers 28:30, and at the consecration of the priests Leviticus 9:3; while the smooth-haired goat appears to have been generally offered for the other sacrifices Psalms 50:9; Isaiah 1:11.