Bhagavad Gita 5.6

Without concentration, O Mighty One, renunciation is difficult. But the sage who is always meditating on the Divine, shall soon attain the Absolute.

संन्यासस्तु महाबाहो दुःखमाप्तुमयोगतः।
योगयुक्तो मुनिर्ब्रह्म नचिरेणाधिगच्छति॥

saṃnyāsastu mahābāho duḥkhamāptumayogataḥ|
yogayukto munirbrahma nacireṇādhigacchati||

English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).