Some people reason like this. The Gita lists destiny among the five causes of any action. The same Gita says that we have no right to the fruit. So the result is settled beforehand and nothing is in our hands. Why work at all?
The reasoning is built from real sentences of the Gita, so it should be answered from the Gita. In short: destiny is one of five causes, not the whole cause, and the very verse that takes away the right to the fruit also forbids clinging to inaction. The whole subject is in Who Is the Doer?.
Where the idea comes from
Two things feed it. One, destiny is named in the list of causes (Gita 18.14). Two, the right to the fruit is denied (Gita 2.47). The mind joins them and says that the outcome is not ours, so why strain? Most of us have stood at a point where the outcome was not in our hands even after hard work. In that tiredness this thought brings relief.
Counting the five
विविधाश्च पृथक्चेष्टा दैवं चैवात्र पञ्चमम् ॥ १८.१४ ॥
vividhāśh cha pṛthak cheṣhṭā daivaṁ chaivātra pañchamam || 18.14 ||
The seat of action, the doer, the various kinds of instruments, the many different kinds of efforts, and here, destiny as the fifth.
Look at the list: the base, the doer, the various instruments, the many kinds of effort, and, fifth, destiny (Gita 18.14). The fourth cause is effort. If everything were destiny, there would be no need to name four other causes. The Lord then adds that whatever is undertaken by body, speech or mind, right or wrong, has these five causes (Gita 18.15). The list does not lessen destiny, but it does not let the other four be dropped either.
2.47 has already replied
मा कर्मफलहेतुर्भूर्मा ते सङ्गोऽस्त्वकर्मणि ॥ २.४७ ॥
mā karmaphalahetur bhūr mā te saṅgo 'stv akarmaṇi || 2.47 ||
You have a right to perform your prescribed duty, but you are never entitled to the fruits of action. Never consider yourself the cause of the results of your activities, and never be attached to inaction.
The verse has three parts. The right is to action alone, not to the fruit. Do not be the cause of the fruit. And let there be no attachment to inaction (Gita 2.47). The third part blocks the very conclusion that the reasoning above draws. The verse from which "the fruit is not ours" is taken says in the same breath, "do not fold your hands." And the Lord says that without action even the body cannot be kept going (Gita 3.8).
Effort is never wasted
It may be said that if the outcome did not come, the effort was lost. The Gita denies that as well. On this path no beginning is lost, there is no adverse result, and even a little of it protects from great fear (Gita 2.40).
पार्थ नैवेह नामुत्र विनाशस्तस्य विद्यते।
न हि कल्याणकृत्कश्चिद्दुर्गतिं तात गच्छति॥ ६.४०॥
pārtha naiveha nāmutra vināśas tasya vidyate
na hi kalyāṇa-kṛt kaścid durgatiṁ tāta gacchati || 6.40 ||
The Blessed Lord said: O Pārtha, such a seeker is never lost either in this world or in the next. O dear Arjuna, one who performs righteous and beneficial actions never meets with a bad destiny.
Later the Lord says that one who does good never meets a bad end (Gita 6.40). Together the two show that effort is not only a tool for producing results. It builds something in the person: steadiness, protection from fear, and a direction for what comes next. The fruit may slip out of the hand, but what the effort gave the one who made it does not slip away.
Two opposite mistakes
| Mistake | What it says | Its effect | The Gita's correction |
|---|---|---|---|
| Everything depends on me | The outcome is wholly in my hands | Swelling in success, crushing in failure | The doer is one of five (18.14) |
| Everything depends on fate | My doing changes nothing | Slackness, putting off, despair | Efforts are one of five, and the right is to action (18.14, 2.47) |
One list cures both mistakes. The first makes the doer the only cause; the second reduces effort to nothing.
What is destiny?
The text gives only the word: destiny as the fifth. Teachers take it in different ways. Some take it as the unseen result of earlier actions, some as the Lord's ordering, and some as the unseen circumstances that no one controls. The verse does not settle which of these is meant, and no side is taken here. What all agree on is that destiny is one cause, counted with four others.
An example: Divya and the exam
Take Divya, whose exam is a week away, after a week that went badly for her for reasons she could not help. Her mind says: what will be will be, so why study?
She draws two columns on a page. In the first, "my part": which subjects for two hours a day, which old papers, when to sleep. In the second, "the open part": what questions will come, how she will feel on the day, who will mark the paper. She does the things in the first column every day. She looks at the second and does not feed worry on it. When the results come, whatever they are, she already has what the effort built: subjects learned, a habit set, and a steadier mind.
- Where have I folded my hands by saying "what is to be will be"?
- What is my part in it, and what is the open part?
- If the outcome does not go my way, what will the effort already have given me?
- What is the first thing in my column for today?
The right meaning
Destiny is the part of the result that is not in our hands, and effort is the part that is. The Gita asks us to let go of the first, as clinging to the fruit, and to do the second. That is why it refuses a right to the fruit and in the same breath refuses attachment to inaction.
Going deeper
The table of the five causes, how they relate and the commentators' streams are in Who Is the Doer?. The other misreading of this topic, that "I am not the doer" means I am not responsible, is treated separately.