She expanded her work to include guidance, small financial support, job-seeking assistance, and other aid to newly released prisoners in an attempt to help them transition to the outside world.

During the last year of the Civil War, at the age of 19 Rebecca Elliot married Union colonel and attorney John Armstrong Foster (March 5, 1833-February 11, 1890)[4] on February 28, 1865, at Calvary Church in New York.

[5] One of her daughters later said she remembered family stories that a member of President Abraham Lincoln's cabinet attended her parents' wedding.

[6] Foster initially supported herself and her daughters from her pay working for the Presbyterian City Mission Society of New York.

From the mid-1880s on, Rebecca Foster worked assisting people who were charged and defendants in the New York legal system, especially before they went to trial.

She acted as an unofficial court investigator and advisor, trying to ascertain the facts of each inmate's case and giving her judgment as to whether the person was innocent or guilty of charges.

[1][5] She also worked to support former prisoners in their lives after they were released, taking a role as a kind of ad hoc "probation officer" well before that formal system was established in New York in 1901.

Her funeral on February 25, 1902, at the Calvary Church in Manhattan, was attended by many people whom she had saved from conviction, notable reform figures, and officials and court judges.

It was rededicated on June 25, 2019, when it was installed in the lobby of the New York Supreme Court located at 60 Centre Street in Manhattan.