One should not give up anything which can be utilized in the service of the Lord. That is a secret of devotional service. Anything that can be utilized in advancing Kṛṣṇa consciousness and devotional service should be accepted. For instance, we are using many machines for the advancement of our present Kṛṣṇa consciousness movement, machines like typewriters, dictaphones, tape recorders, microphones and airplanes. Sometimes people ask us, “Why are you utilizing material products if you condemn the advancement of material civilization?” But actually we do not condemn. We simply ask people to do whatever they are doing in Kṛṣṇa consciousness. This is the same principle on which, in the Bhagavad-gita, Kṛṣṇa advised Arjuna to utilize his fighting abilities in devotional service. Similarly, we are utilizing these machines for Kṛṣṇa’s service. With such sentiment for Kṛṣṇa, or Kṛṣṇa consciousness, we can accept everything. If the typewriter can be utilized for advancing our Kṛṣṇa consciousness movement, we must accept it. Similarly, the dicta phone or any other machine must be used. Our vision is that Kṛṣṇa is everything. Kṛṣṇa is the cause and effect, and nothing belongs to us. Kṛṣṇa’s things must be used in the service of Kṛṣṇa.
The impersonalists who try to avoid everything material may undergo severe austerities, but they miss the opportunity of being engaged in the service of the Lord. Thus their renunciation is not sufficient for perfection. There are many instances where, following such artificial renunciation without any contact with devotional service, the impersonalist again fell down and became attracted to the material contamination. There are many supposed renouncers even at the present moment who officially become sannyasis or renouncers and outwardly claim that spiritual existence is truth and material existence untruth. In this way, artificially they make a show of renunciation of the material world. However, because they cannot reach the point of devotional service, they fail to achieve the goal and again come back to material activities, such as philanthropic work, political agitation, etc. There are many instances of so-called sannyasis who gave up the world as untruth, but again came to the material world because they were not seeking their real repose at the lotus feet of the Lord.
Source: A.C. Bhaktivedanta Swami Prabhupada (2011 edition), “The Nector of Devotion”, Page 114 & 115