פירוש על שבת 44:1

Second tithe: Dinar-coins through which he redeemed second tithe may not be weighed against mundane dinar-coins (as a counter-weight) to see that they are undiminished (that their weight is a complete measure).

Granted, if you say [that] when Rav and Shmuel disagree, it is from lamp to lamp in actuality and not with a wood chip, and it is about this that Shmuel permits, since he is not concerned that he weakens it; but with a wood chip, he concedes. Then this is no refutation. For the body of these dinar-coins of the mundane are not [of] a commandment. And even though they are needed for a commandment, they are similar to the wood chip. However if you say Shmuel also permits [it] with a wood chip - since it is [for] the need of a commandment - then it is a refutation. For [the Tosefta] forbade to weigh [the coins], even though it was for the need of a commandment.

His weights not be precisely equal: Lest he not find them to be good; or he find them to [weigh] more, and spare them and not redeem the tithe upon them. So it comes out that he showed contempt towards the tithe without a need.

And render them unsanctified: Meaning to say, he will leave them unsanctified, as they are.