The phrase kaard bah ustu;xvaan rasiidan is a famous Persian idiom. 'For the knife to arrive at the bone'-- that is, to be in harsh trouble and difficulty. In order to prove it, what a beautiful and hair-raising first line he has composed: that all the flesh of the body has become water and flowed away.
It's obvious that in such a situation the knife will, willy-nilly, reach to the bone. There's a common belief about poisonous snakes, that if they bite someone, the whole body becomes water and flows away. In this way in the first line the implication of the 'poison of grief' or the 'serpent of passion' has also been established.
For the 'serpent of passion', see, in the sixth divan [{1862,7}]:
vaamiq-o-kohkan-o-qais nahii;N hai ko))ii
bhakh gayaa ((ishq kaa az;dar mire ;Gam-;xvaaro;N ko
[Vamiq and Kohkan and Qais-- none of them is around
the serpent of passion ate up my sympathizers/'grief-eaters']
The address to the 'dear ones' brings the present verse nearer to everyday life. In this address there's a suspicion of sarcasm and helplessness both.
