Said the holy lamp: ‘Now surely the matter is in its place, and this is the clarification of the matter. And this is: (Ex. 22:28) Your ‘fullness’ and your ‘tear’ offerings do not delay... And it is said:lxxviiBT Mo’ed Qatan 18b ‘Lest another precede him through mercy or prayer.’
This sin, when a man mingles ‘the drop’ of the firstborn, through coupling with ‘menstruant maidservant, gentile, whore’, for this causes another to take his true coupling partner. And it is ‘measure for measure’.
And therefore: (Ex. 23:19) The first of the fruits of your land, you shall bring to the house of Y”Y ELoQeYKha... is followed by... you shall not cook a kid in its mother’s milk, because that resulting child is a mixture, which emerges in a state of forbidden-mixing (kilayim) – from a woman that is not of his type. For she is described as (Gen. 2:18) against him (kenegdo).