Chapter 2 · The Yoga of Knowledge · Krishna said
Bhagavad Gita 2.40 — No effort is wasted
नेहाभिक्रमनाशोऽस्ति प्रत्यवायो न विद्यते। स्वल्पमप्यस्य धर्मस्य त्रायते महतो भयात् ॥
nehābhikramanāśo'sti pratyavāyo na vidyate | svalpamapyasya dharmasya trāyate mahato bhayāt ||
Meaning
On this path no effort is ever wasted and there is no harm from falling short. Even a little of this practice protects one from great fear.