“Against that time, if ever that time come”
The phrase 'Against that time' opens the first three quatrains in succession (lines 1, 5, and 9), a device called anaphora — deliberate repetition at the start of consecutive units. The repetition turns each quatrain into a new rehearsal of the same dread: the speaker is bracing for a future he expects will come.
historical The sonnet form“thy love hath cast his utmost sum, Call'd to that audit by advis'd respects”
'Cast his utmost sum' means totalled up its final account — drawn from bookkeeping: 'to cast' was to add up figures; 'sum' is the total. An 'audit' was a formal examination of accounts, here imagined as a reckoning in which the beloved reviews the relationship like a ledger and decides it no longer balances. 'Advis'd respects' means careful, deliberate considerations — not passion but cool judgement.
“when thou shalt strangely pass, And scarcely greet me”
'Strangely' here means 'like a stranger' — in the manner of someone who does not know you. To 'pass' is to walk by. The beloved will walk past the speaker in the street and barely glance at him, as if they have never met. The word had no implication of oddness; it described the behavior of a stranger (from Latin 'extraneus').
“do I ensconce me here, Within the knowledge of mine own desert”
'Ensconce' means to shelter or entrench oneself — from 'sconce,' a small protective fortification. The speaker takes up a defensive position inside 'mine own desert,' meaning 'my own deserving' — what he merits, which he admits is not enough to hold the beloved. He retreats into the knowledge of his own unworthiness as if into a fort.
“this my hand, against my self uprear, To guard the lawful reasons on thy part”
The sonnet sustains an extended legal conceit across its last six lines: the speaker raises his hand to give sworn testimony ('uprear' = raise a hand as in an oath), but he is testifying against himself, arguing the 'lawful reasons' — legal grounds — for the beloved's departure. The couplet completes the image: the beloved has the 'strength of laws' to leave, and the speaker 'can allege no cause' — legal language for failing to state a valid defence. He acts as both defendant and his own prosecutor.
historical The sonnet form