Padma Purana:
Sampradayavihina ye mantraste nisphalaMatah
Atah kalau bhavisyanti catvarah Sampradayinah
Sri brahma rudra sanaka vaisnava Ksitipavanah
Catvaraste kalau bhavya hyutkale Purusottamat
Ramanujam sri svichakre madhvacaryam caturmukhah
Srivisnusvaminam rudro nimbadityam catuhsanah

All mantras which have been given (to disciples) not in an authorised Sampradāya are fruitless. Therefore, in Kali Yuga, there will be four bona-fide Sampradāyas. Each of them were ignaugurated by Śrī Devī and known as the Śrī Sampradāya, Lord Brahmā and known as the Brahmā Sampradāya,Lord Rudra and known as the Rudra Sampradāya; and the Four Kumāras and known as Sanakādi Sampradāya. Śrī Devī made Rāmānujācārya the head of that lineage. So too Lord Brahmā appointed Madhvācārya, Lord Rudra appointed Viṣṇusvāmī and the four Kumaras chose Nimbāditya (an epithet for Śrī Nimbārkācārya).

SB 5.6.11
te ca hy arväktanayä nija-loka-yätrayändha-paramparayäçvastäs tamasy andhe svayam eva prapatiñyanti.
TRANSLATION
Low-class people, due to their gross ignorance, introduce a system of religion that deviates from the Vedic principles. Following their own mental concoctions, they automatically fall down into the darkest regions of existence.

Srila Prabhupada Bombay September 30,1973
"That paramparä should be followed. Evaà paramparä-präptam imaà räjarñayo viduù [Bg. 4.2]. If we want to understand really Vedic literature, then we must follow the paramparä system. There are four sampradäyas, paramparä: the Rämanuja Sampradäya, Madhväcärya Sampradäya, Viñëu Svämé Sampradäya, Nimbärka Sampradäya. So we belong to the Madhväcärya Sampradäya This sampradäya, äcärya-sampradäya, is going on all over India. So every sampradäya has got his commentary on the Brahma-sütra. Therefore Kåñëa says here, brahma sütra-padaiç caiva hetumadbhir viniçcitaiù [Bg. 13.5]. Unless a sampradäya, the four sampradäyas, they do not comment on the Brahma-sütra, he'll not..., that sampradäya is not accepted. And if you do not accept the sampradäya..., sampradäya-vihénä ye manträs te niñphalä matäù.
If you do not take your initiation mantra from the sampradäya, then it is useless. Now, there are so many
apasampradäya. They do not come in disciplic succession, but becomes guru, teacher. Therefore everything is topsy-turvied. Nobody has got fixed idea what is God. Everyone has created his own philosophy. The whole thing is now confused.
Therefore Kåñëa specifically mentions, Brahma-sütra.Brahma-sütra-padaiç caiva hetumadbhir viniçcitaiù [Bg. 13.5]. The sampradäya must have understanding of the Brahma-sütra, Vedänta-sütra. So all the sampradäyas, they have got their commentary on the Vedänta-sütra and... Even Çaìkaräcärya. But his commentary is not accepted by the Vaiñëava äcäryas because he has tried to derive some meaning, interpretation. "