Romans 7:2

For the woman that hath. husband is bound by law to the husband while he liveth; but if the husband die, she is discharged from the law of the husband.

'Bound by law' -stands bound (Robertson p. 366) (Matthew 19:6) 'The married wife stands bound to the living husband by law. Certainly not only by Jewish but equally by Roman, yea by barbarian law.' (Lenski pp. 443-444)

Here is. specific example of the principle cited in verse 1.

'Discharged' -'Released' (NASV). 2673. katargeo kat-arg-eh'-o; from 2596 and 691; to be (render) entirely idle (useless), literally or figuratively: -abolish, cease, cumber, deliver, destroy, do away, become (make) of no (none, without) effect, fail, loose, bring (come) to nought, put away (down), vanish away, make void.

'the law of the husband' -i.e. the law which binds her to the husband. That former relationship is made void, in. sense she dies to that law with the husbands death.