Would not the teaching of a future probation tend to make the people careless and sinful in this life, and knowing that they were to have a second chance in the life to come?

Not nearly as much as to teach that a hardened wretch by a deathbed confession would immediately be ushered into Heaven! Besides, a future probation would not signify a "second chance," save for a limited few, the Church of Christ, now being selected out of the world (`Acts 15:14`) to be the Bride, the Lamb's Wife. Most of the criminals inhabiting the jails and prisons of our land are, or were, members of some religious system that taught the sinner-hardening doctrine of eternal torment. Did the false teaching defer them from committing crime? Those who believe that the Creator is a God of love, and mercy, and justice, and that He has arranged seasons of blessings for the world in the coming age, when mankind is to have its only chance of salvation, are invariably ennobled, and elevated to a higher plane of morality, with greater reverence for their Creator, a God, whom to know, is to love. The truth sanctifies, while the error debases.