In mercantile pursuits the business man who gives a letter of recommendation to a friend to enable him to obtain credit from a stranger is regarded as morally responsible for the integrity of his friend and his ability to meet his obligations.
 Ulysses S. Grant, State of the Union Address. copy citation

Context

“If bad men have secured places, it has been the fault of the system established by law and custom for making appointments, or the fault of those who recommend for Government positions persons not sufficiently well known to them personally, or who give letters indorsing the characters of office seekers without a proper sense of the grave responsibility which such a course devolves upon them. A civil-service reform which can correct this abuse is much desired. In mercantile pursuits the business man who gives a letter of recommendation to a friend to enable him to obtain credit from a stranger is regarded as morally responsible for the integrity of his friend and his ability to meet his obligations. A reformatory law which would enforce this principle against all indorsers of persons for public place would insure great caution in making recommendations. A salutary lesson has been taught the careless and the dishonest public servant in the great number of prosecutions and convictions of the last two years.” source