A world in which naught can be perceived save strife, quarrels and corruption is bound to become the seat of the throne, the very metropolis, of Satan.
(Baha'u'llah, Tablets of Baha'u'llah, p. 176)
The attributes of God are love and mercy; the attribute of Satan is hate. Therefore, he who is merciful and kind to his fellowmen is manifesting the divine attribute, and he who is hating and hostile toward a fellow creature is satanic. God is absolute love, even as Jesus Christ has declared, and Satan is utter hatred. Wherever love is witnessed, know that there is a manifestation of God's mercy; whenever you meet hatred and enmity, know that these are the evidences and attributes of Satan.
(Abdu'l-Baha, The Promulgation of Universal Peace, p. 40)
Therefore, there is no satanic tree whatever -- Satan being a product of human minds and of instinctive human tendencies toward error.
(Abdu'l-Baha, The Promulgation of Universal Peace, p. 230)
The reality underlying this question is that the evil spirit, Satan or whatever is interpreted as evil, refers to the lower nature in man. This baser nature is symbolized in various ways. In man there are two expressions: One is the expression of nature; the other, the expression of the spiritual realm. The world of nature is defective. Look at it clearly, casting aside all superstition and imagination.
God has never created an evil spirit; all such ideas and nomenclature are symbols expressing the mere human or earthly nature of man. It is an essential condition of the soil of earth that thorns, weeds and fruitless trees may grow from it. Relatively speaking, this is evil; it is simply the lower state and baser product of nature.
(Abdu'l-Baha, The Promulgation of Universal Peace, p. 294)