B.G 14.24 and 25

samaduḥkhasukhaḥ svasthaḥ samaloṣṭāśmakāñcanaḥ। tulyapriyāpriyo dhīrastulyanindātmasaṃstutiḥ ॥24॥

mānāpamānayostulyastulyo mitrāripakṣayoḥ। sarvārambhaparityāgī guṇātītaḥ sa ucyate ॥25॥

One who is equanimous in both sorrow and happiness, self-possessed, and regards a clod, stone, and gold as equal; who is equal towards the pleasant and unpleasant, steady, and remains unaffected by blame or praise; the person who remains balanced in honour and dishonour, treats friends and enemies alike, and has renounced all undertakings is considered to have transcended the (three) qualities.

Gīta Bhāshya 14.24 and 25

The way to interpret the phrases such as 'tulyapriyāpriyaḥ', i.e. equal towards the pleasant and unpleasant, is already explained (at 2.55, while describing the characteristics of 'Sthita-prajna', one who is equanimous).

tulyatvārtha uktaḥ purastāt ॥25॥

The way to interpret the phrases such as 'tulyapriyāpriyaḥ', i.e. equal towards the pleasant and unpleasant, is already explained (at 2.55, describing the characteristics of 'Sthita-prajna', one who is equanimous).