Be thou as a flame of fire to My enemies and a river of life eternal to My loved ones...
Know thou that polygamy is not permitted under the law of God, for contentment with one wife hath been clearly stipulated. Taking a second wife is made dependent upon equity and justice being upheld between the two wives, under all conditions. However, observance of justice and equity towards two wives is utterly impossible. The fact that bigamy has been made dependent upon an impossible condition is clear proof of its absolute prohibition. Therefore it is not permissible for a man to have more than one wife.
It is true that Bahá'u'lláh lays on every Bahá'í the duty to teach His Faith. At the same time, however, we are forbidden to proselytize, so it is important for all believers to understand the difference between teaching and proselytizing. It is a significant difference and, in some countries where teaching a religion is permitted, but proselytizing is forbidden, the distinction is made in the law of the land. Proselytizing implies bringing undue pressure to bear upon someone to change his Faith. It is also usually understood to imply the making of threats or the offering of material benefits as an inducement to conversion. In some countries mission schools or hospitals, for all the good they do, are regarded with suspicion and even aversion by the local authorities because they are considered to be material inducements to conversion and hence instruments of proselytization.(The Universal House of Justice, Messages 1963 to 1986, p. 513)