At the time Elizabeth Proctor speaks these words, her husband John is being taken to hang. The Reverand John Hale begs Elizabeth to force a lie out of John Proctor to save his life, but she refuses, instead delivering this line. There are a few historical lenses you can view this through: an allegorical and a literal one. To understand the literal lens, you have to understand a bit about the Puritan way of life - the one the town of Salem, Massachusetts was founded on. Puritanism was a particularly radical branch of Protestantism which believed - among other things - that earthly actions were no guarantee of one's salvation. Some were simply cut off from the beginning, and others had to be chosen by God for salvation. Inherent in this belief was a challenge to Church authority, since no priest held sway over an individual's admittance to Heaven.
One way of interpreting Elizabeth's line here is that she's confident that, regardless of the verdict of the trials and his impending death sentence, in the eyes of God, John has done right by remaining an honest man - he retains his "goodness," vital in his passage into the afterlife and Heaven. That goodness is far more valuable than his life on earth, and Elizabeth and John Proctor seem quietly acknowledge that before he's carried off to meet his fate.
