If one possesses the love of God, everything that he undertakes is useful, but if the undertaking is without the love of God, then it is hurtful and the cause of veiling one’s self from the Lord of the Kingdom. But with the love of God every bitterness is changed into sweetness and every gift becometh precious. For instance, a musical and melodious voice imparteth life to an attracted heart but lureth toward lust those souls who are engulfed in passion and desire.
With the love of God all sciences are accepted and beloved, but without it, are fruitless; nay, rather the cause of insanity. Every science is like unto a tree; if the fruit of it is the love of God, that is a blessed tree. Otherwise it is dried wood and finally a food for fire.
Abdu’l-Baha’-Tablets, Vol. III pp. 687-688