योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-210, verse-40

सकलार्थनिरासेन यद्यत्संवेद्यते चिरम् ।
तदेव प्राप्यतेऽवश्यं सर्वत्रैवान्यभावितम् ॥ ४० ॥

sakalārthanirāsena yadyatsaṃvedyate ciram ,
tadeva prāpyate'vaśyaṃ sarvatraivānyabhāvitam 40

40. He who adheres steadily to his own purpose, by utter disregard of all other objects in his view; is said to be firmly fixed to his point, and is sure to reap his success at the end.