Better stop short than fill it to the brim.
Oversharpen the blade, and the edge will soon be blunt.
Amass a store of gold and jade, and no one can protect it.
Claim wealth and titles, and disaster will follow.
Retire when the work is done.
This is the way of heaven
 The Ma wang tui text and Lau have 'hammer it to a point'. (As I was saying when so rudely interrupted) Cheng, rather intriguingly, has 'measure and fit a crossbrace'...
 The Ma wang tui text says that of themselves they bring on disater.
Cheng's commentary reads: To grasp after until one's hand is full means one has reached the limit: this is not as good as knowing when to stop. Although one measures a crossbrace to fit, it cannot last long since the piece is small and the material weak. Wang Pi took 'crossbrace' to mean 'sharp'. This is unreasonable. The character for crossbrace belongs to the wood radical and thus cannot have anything to do with metal (*).
If something cannot be safeguarded, let it go. One who is proud will bring trouble upon himself.
Who is capable of imitating the Tao of heaven? Who bring forth flowers in the springtime and fruit in the fall, and, having done so, retire?
(*) Being all which as it ever so may, ALL the other texts I have consider the idea as that of sharpening, and Waley even goes so far as to change the first line to 'Stretch a bow to the very full/ And you will wish you had stopped in time', so as to be in harmony with the idea of swords and sharpening.
Wang's commentary (he reads the first line as 'With it firmly in hand, he goes on to fill it up, but it would be better to quit')(*): 'Firmly in hand' means not to let virtue (teh) go. Not only does he not let his virtue go, he goes further and fills it up. The power of such a one will surely be toppled. Thus 'it would be better to quit', which means that it would be even better if if one had no virtue or sense of achievement at all.
If, forging the end of a sword, one goes further and grinds it sharper until it snaps off, its characteristic property is destroyed. Thus 'it could not last long'.
(*) Which chimes, to a degree, with Cheng's 'To grasp after until one's hand is full means one has reached the limit'.
Concerning the last line he says: The four seasons move on. As soon as one has achieved what it should, it moves on to the next.
Quite frankly, what strikes me here is that this is a call not only for a sense of proportion (which is fairly obvious), but also - and far more importantly - for a sense of humour. An ability to look at things and let 'em go, do things and shrug 'em off... Walking lightly on this small blue planet.
It's not for nothing that I refer to my enterprise here as 'mist'... Not only does this adequately describe what keeps my ears apart, but it also seems to me to be a fair description of the ever-fountaining dragon-dance of space-dancing-space-into-space that is the world of becoming.