We send the Wave to find the Wave — Message Timing

We send the Wave to find the Wave-1
An Errand so divine,
The Messenger enamored too,
Forgetting to return,
We make the wise distinction still,
Soever made in vain,
The sagest time to dam the sea is when the sea is gone-
(F.1643/J.1604)
[1] send, Wave:: a wave of thoughts in letters sent. find, Wave:: a wave of responding enthusiasm.
[3] Messenger:: a letter.
[4] Forgetting to return:: no mail ever returned.
[5] distinction:: qualification of the letters sent at the right timing.
[7] dam the sea:: to calm sea waves; conquer large wave of a person's emotion, sea is gone:: in low tide, a person in low mood.