All different kinds of sacrifice are performed just to satisfy Lord Narayana with a view to reach Him, and the best sacrifice recommended in this age of Kali is sankirtana-yajna, the mainstay of the devotional service of a narayana-para devotee
SB Canto 2
The Vedic literatures are made by and are meant for the Supreme Lord, the demigods are also meant for serving the Lord as parts of His body, the different planets are also meant for the sake of the Lord, and different sacrifices are performed just to please Him.
According to the Vedānta-sūtras (śāstra-yonitvāt), the Supreme Lord is the author of all revealed scriptures, and all revealed scriptures are for knowing the Supreme Lord. Veda means knowledge that leads to the Lord. The Vedas are made just to revive the forgotten consciousness of the conditioned souls, and any literature not meant for reviving God consciousness is rejected at once by the nārāyaṇa-para devotees. Such deluding books of knowledge, not having Nārāyaṇa as their aim, are not at all knowledge, but are the playgrounds for crows who are interested in the rejected refuse of the world. Any book of knowledge (science or art) must lead to the knowledge of Nārāyaṇa; otherwise it must be rejected. That is the way of advancement of knowledge. The supreme worshipable Deity is Nārāyaṇa. The demigods are recommended secondarily for worship in relation to Nārāyaṇa because the demigods are assisting hands in the management of the universal affairs. As the officers of a kingdom are respected due to their relation to the king, the demigods are worshiped due to their relation to the Lord. Without the Lord's relation, worship of the demigods is unauthorized (avidhi-pūrvakam), just as it is improper to water the leaves and branches of a tree without watering its root. Therefore the demigods are also dependent on Nārāyaṇa. The lokas, or different planets, are attractive because they have different varieties of life and bliss partially representing the sac-cid-ānanda-vigraha (Bs. 5.1). Everyone wants the eternal life of bliss and knowledge. In the material world such an eternal life of bliss and knowledge is progressively realized in the upper planets, but after reaching there one is inclined to achieve further progress along the path back to Godhead. Duration of life, with a proportionate quantity of bliss and knowledge, may be increased from one planet to another. One can increase the duration of life to thousands and hundreds of thousands of years in different planets, but nowhere is there eternal life. But one who can reach the highest planet, that of Brahmā, can aspire to reach the planets in the spiritual sky, where life is eternal. Therefore, the progressive journey from one planet to another culminates in reaching the supreme planet of the Lord (mad-dhāma), where life is eternal and full of bliss and knowledge. All different kinds of sacrifice are performed just to satisfy Lord Nārāyaṇa with a view to reach Him, and the best sacrifice recommended in this age of Kali is saṅkīrtana-yajña, the mainstay of the devotional service of a nārāyaṇa-para devotee.