SB 4.24.76
ya imam sraddhaya yukto
mad-gitam bhagavat-stavam
adhiyano duraradhyam
harim aradhayaty asau
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Although rendering devotional service to the Supreme Personality of Godhead and worshiping Him are very difficult, if one vibrates or simply reads this stotra [prayer] composed and sung by me, he will very easily be able to invoke the mercy of the Supreme Personality of Godhead.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is especially significant that Lord Siva is a pure devotee of Lord Vasudeva. Vaisnavanam yatha sambhuh: “Amongst all Vaisnavas, Lord Siva is the topmost.” Consequently Lord Siva has a sampradaya, a Vaisnava disciplic succession, called the Rudra sampradaya. At the present moment those who belong to the Visnusvami sampradaya of Vaisnavas come from Rudra, Lord Siva. To become a devotee of Lord Krsna, Vasudeva, is very, very difficult. The word especially used in this connection is duraradhyam. The worship of the demigods is not very difficult, but becoming a devotee of Lord Vasudeva, Krsna, is not so easy. However, if one adheres to the principles and follows in the footsteps of the higher authorities, as advised by Lord Siva, one can easily become a devotee of Lord Vasudeva. This is also confirmed by Prahlada Maharaja. Devotional service cannot be practiced by a mental speculator. Devotional service is a special attainment which can be acquired only by a person who has surrendered unto a pure devotee. As confirmed by Prahlada Maharaja, mahiyasam pada-rajo-’bhisekam niskiñcananam na vrnita yavat: “Unless one accepts the dust of the lotus feet of a pure devotee, who is free from all material contamination, one cannot enter into the devotional service of the Lord.” (Bhag. 7.5.32)