Exile and imprisonment are decreed for the thief, and, on the third offence, place ye a mark upon his brow so that, thus identified, he may not be accepted in the cities of God and His countries. Beware lest, through compassion, ye neglect to carry out the statutes of the religion of God; do that which hath been bidden you by Him Who is compassionate and merciful. We school you with the rod of wisdom and laws, like unto the father who educateth his son, and this for naught but the protection of your own selves and the elevation of your stations. By My life, were ye to discover what We have desired for you in revealing Our holy laws, ye would offer up your very souls for this sacred, this mighty, and most exalted Faith.

Exile and imprisonment are decreed for the thief
Bahá’u’lláh states that the determination of the degree of penalty, in accordance with the seriousness of the offence, rests with the House of Justice (Q&A 49). The punishments for theft are intended for a future condition of society, when they will be supplemented and applied by the Universal House of Justice.