तस्माद्यस्य महाबाहो निगृहीतानि सर्वशः।इन्द्रियाणीन्द्रियार्थेभ्यस्तस्य प्रज्ञा प्रतिष्ठिता॥
tasmād yasya mahā-bāho nigṛhītāni sarvaśaḥindriyāṇīndriyārthebhyas tasya prajñā pratiṣṭhitā
Word by word
The verse says
So, Arjuna: the person whose senses are completely held back from what they reach for — his understanding is firmly set.
In plain words
Krishna repeats the conclusion. Almost word for word from verse 58.
He has now said this three times in eleven verses. That is not carelessness; the repetition is the teaching method.
And tasmāt — therefore. This is the summing-up of everything since verse 60.
Where you've felt this · in sport
A coach says the same sentence at the end of every session for a season. By the end nobody is listening to it, and every one of them can hear it in their head during a match.
Going deeper
The refrain tasya prajñā pratiṣṭhitā — his understanding is firmly set — has now closed verses 58, 61 and 68.
Each time it arrives after a different account of how the senses go wrong. Verse 58 after the tortoise. Verse 61 after the admission that even the wise are overpowered. Here after the boat. Same conclusion, three different roads to it.
This is how oral teaching works, and reading the Gita as a written argument can make the repetition look like padding. It is not. The phrase is a landing point, and each return to it is meant to land somewhere slightly different because of what has been said in between.
Nigṛhītāni sarvaśaḥ — held back completely, on all sides. The word is stronger than the tortoise image, and a reader might reasonably feel the tension with verse 64, where the settled person moves freely among objects.
The tension is real and the commentators handle it in different ways. The most workable reading is that nigṛhīta describes the capacity rather than a permanent posture: the senses are held in the sense that they can be, not that they are always drawn in.