1:
Our mishnah is concerned with the status of wine that is being moved from one place to another. A Jew has asked a non-Jew to help him in this task, and for the purposes of our present mishnah it makes no difference whether the services of the non-Jew are paid for or not. The problem which lies at the heart of our mishnah is the possibility that the non-Jew will take advantage of the absence of the Jew and drink some of the wine, thus rendering the whole cask yeyn nesekh.

2:
We have already learned [AZ 061] that if wine is considered to be "under guard" or "watched" then a non-Jew may be left alone with the casks: he will be anxious that the Jewish guard might return at any moment and catch him taking some of the wine. So, the first clause of our mishnah is simple: if the non-Jew can expect the return of the Jew at any moment he will be too anxious to try to taste some of the wine. It may therefore be assumed that it has not been rendered yeyn nesekh.

3:
The problem begins in the next clause of our mishnah. If the Jew tells the non-Jewish assistant that he will be gone for some time - perhaps on some urgent errand - or if the circumstances are such that the non-Jew can assume that the Jew will be gone for some time and is not likely to suddenly re-appear, what then is the status of the wine?

4:
On this matter there is a difference of opinion between Rabban Shim'on ben-Gamli'el and the rest of the sages. The sages hold that one must judge what could be done in the time span of the Jew's absence. If he was absent long enough for the non-Jew to open the cask, re-seal it and to tidy up the area of the seal then one must assume that the wine has become yeyn nesekh.

5:
We must imagine a cask or barrel which has a lid or a bung. It was customary to secure these lids or these bungs with a clay seal. In order to get a surreptitious drink of wine one would have to drill a hole in the lid or remove it completely and having drunk one's fill one would have to replace the lid or seal the hole and renew the clay seal. It would also be necessary to tidy up the area around the seal so that it would not be immediately obvious that someone had meddled with the cask. The same would apply if the cask had a bung, which is a wooden stopper in the side of the cask which can be removed in order to remove wine from the cask. The bungs too were sealed with clay.

6:
We can consider for a moment an interesting linguistic matter. The story in the Torah of Balaam, the non-Jewish prophet who was hired by the king of Moab to curse the Israelites, is well known. Balaam tries to curse but God turns each curse into a blessing. Balaam utters his benedictions in beautiful Hebrew poetry. A couple of times, in a phrase used to introduce a new curse/blessing he describes himself as "open-eyed". For example he says [Numbers 24:3-4]:

And again he says [Numbers 24:15-16]

The word used when Balaam describes himself as being 'open-eyed' is very unusual and very archaic. Yet the same verb is used in our present mishnah to indicate the surreptitious opening of a cask.

7:
We must now consider the opinion of Rabban Shim'on ben-Gamli'el. The difference between his view and that of the rest of the sages is, in fact, one of time. He holds that it is not enough just to tidy the area of the renewed clay. He holds that if the clay seal is still wet when the Jew returns it would be obvious that someone had interfered with the cask, so there is no doubt that the wine has been rendered yeyn nesekh. So that cannot be the intention of our mishnah. But, if the Jew was absent long enough for the clay seal also to dry then the Jew must assume that his wine has become yeyn nesekh.

8:
In his commentary on our present mishnah Rambam offers a slightly different interpretation. In the first clause of our mishnah the wine

It follows that the view of Rabban Shim'on ben-Gamli'el is more lenient than that of the sages (because he requires more time to render the wine yeyn nesekh). Rambam now continues:

The whitewash referred to is some kind of lime solution that was used in mishnaic times as a sealer: for example, the insides of water cisterns were covered with this whitewash in order to render them relatively impervious.