Reference for Moed Katan 25:1
צרם אזן בכור קנסו בנו אחריו משום דאיסורא דאורייתא
One who had [craftily] clipped the ear of his first-born beast', and whose son is penalized after him,<span class="x" onmousemove="('comment',' The firstborn male of 'clean' animals is from birth 'dedicated' or destined for the altar and its flesh is the priests' due (Num. XVIII, 15-18) . It may not be used for work or be shorn, unless it be born blemished or becomes accidentally permanently maimed, when it is no longer fit for sacrifice (Deut. XV, 19-22; cf. Lev. XXII, I8ff) . If the owner cunningly contrives to get it injured either to avoid the trouble and expense of keeping it or to have the flesh, he is penalized to have it buried and is mulcted to half its value for the loss he caused to a priest. V. Shul. 'Ar. Yor. De'ah. 309-310.');"><sup>1</sup></span> [I can reply that] that is because that is [an offence against] a Scriptural prohibition. Or should you cite [the case of], 'One who sold his [non-Jewish] slave to a non-Jew', and whose son was penalized after him, [I can say that] that is because he debarred him daily from the [performance of] religious duties.<span class="x" onmousemove="('comment',' Non-Jewish male slaves who (with their consent) had been circumcised (cf. Gen. XVII. 12-13) and (male and female) ritually received into the household, enjoyed the privileges of resting on the Sabbaths (Ex. XX, 10) and Feasts (Deut. XII, 12, 18) and to partake of holy meats (ibid. XVI, 11) even in the priest's household (Lev. XXII, 11) and to perform such Jewish religious observances as they chose. (Cf. Ber. ');"><sup>2</sup></span>