child of my right hand:

Hebrew, Benjamin: those we trust

loses his right arm with the death of his son

lent to me: our loved ones are lent to us by God on loan and we have to repay

Exacted by thy fate, on the just day: he tries to comfort himself by believing in fate

This is heroic-couplet: we use it to praise someone

(Farewell, thou child of my right hand, and joy; My sin was too much hope of thee, lov'd boy. Seven years thou'wert lent to me, and I thee pay, Exacted by thy fate, on the just day)

Will man lament the state he should envy? To have so soon 'scap'd world's and flesh's rage: enjabment

To have so soon 'scap'd world's and flesh's rage: vanity his son has gone without sin

Will man lament the state he should envy: he believes that his son is in heaven

As what he loves may never like too much: from that day on, he never loved anything as much as he used to.

best piece of poetry: analogy

Will man lament the state he should envy: he loses his sense of fatherhood with the death of his son. he wishes he wasn't a father