SB 4.21.39
yat-sevayasesa-guhasayah sva-rad
vipra-priyas tusyati kamam isvarah
tad eva tad-dharma-parair vinitaih
sarvatmana brahma-kulam nisevyatam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The Supreme Personality of Godhead, who is everlastingly independent and who exists in everyone’s heart, is very pleased with those who follow in His footsteps and engage without reservation in the service of the descendants of brahmanas and Vaisnavas, for He is always dear to brahmanas and Vaisnavas and they are always dear to Him.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is said that the Lord is most pleased when He sees one engage in the service of His devotee. He does not need any service from anyone because He is complete, but it is in our own interest to offer all kinds of services to the Supreme Personality of Godhead. These services can be offered to the Supreme Person not directly but through the service of brahmanas and Vaisnavas. Srila Narottama dasa Thakura sings, chadiya vaisnava-seva nistara payeche keba, which means that unless one serves the Vaisnavas and brahmanas, one cannot get liberation from the material clutches. Srila Visvanatha Cakravarti Thakura also says, yasya prasadad bhagavat-prasadah: by satisfying the senses of the spiritual master, one can satisfy the senses of the Supreme Personality of Godhead. Thus this behavior is not only mentioned in scriptures but also followed by acaryas. Prthu Maharaja advised his citizens to follow the exemplary behavior of the Lord Himself and thus engage in the service of brahmanas and Vaisnavas.