Bhagavad Gita 12.10
And if you are not strong enough to practice concentration, then devote yourself to My service, do all your acts for My sake, and you will still attain the goal.
अभ्यासेऽप्यसमर्थोऽसि मत्कर्मपरमो भव।मदर्थमपि कर्माणि कुर्वन् सिद्धिमवाप्स्यसि॥abhyāse'pyasamartho'si matkarmaparamo bhava|madarthamapi karmāṇi kurvan siddhimavāpsyasi||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).