One verse

Srimad Bhagavatam 11.12.9

11.12.9

यं न योगेन साङ्ख्येन दानव्रततपोऽध्वरै: । व्याख्यास्वाध्यायसन्न्यासै: प्राप्नुयाद् यत्नवानपि ॥ ९ ॥

yaṁ na yogena sāṅkhyena dāna-vrata-tapo-’dhvaraiḥ vyākhyā-svādhyāya-sannyāsaiḥ prāpnuyād yatnavān api

yam
whom
na
not
yogena
by the mystic yoga systems
sāṅkhyena
by philosophical speculation
dāna
by charity
vrata
vows
tapaḥ
austerities
adhvaraiḥ
or Vedic ritualistic sacrifices
vyākhyā
by explaining Vedic knowledge to others
svādhyāya
personal study of the Veda
sannyāsaiḥ
or by taking the renounced order of life
prāpnuyāt
can one obtain
yatna-vān
with great endeavor
api
even

Even though one engages with great endeavor in the mystic yoga system, philosophical speculation, charity, vows, penances, ritualistic sacrifices, teaching of Vedic mantras to others, personal study of the Vedas, or the renounced order of life, still one cannot achieve Me.