In plain words
Those people who constantly follow this teaching of Mine with faith and without fault-finding are also freed from the bondage of action.
Word for word
Those people who constantly follow this view of Mine, with faith and without fault-finding, they too are freed from actions.
The commentators
Bhagavadgītābhāṣyam
यदेतन्मम मतं कर्म कर्तव्यम् इति सप्रमाणमुक्तं तत् तथा —
ये मे मदीयम् इदं मतं नित्यम् अनुतिष्ठन्ति अनुवर्तन्ते मानवाः मनुष्याः श्रद्धावन्तः श्रद्धधानाः अनसूयन्तः असूयां च मयि परमगुरौ वासुदेवे अकुर्वन्तः, मुच्यन्ते तेऽपि एवं भूताः कर्मभिः धर्माधर्माख्यैः ॥ ३१ ॥
In plain words
This view of mine — that action must be done — has been stated along with its proof; and it stands just so —
"Mine" means my own: this settled teaching of mine. "They follow it constantly" means they live by it, without a break. "Mānavāḥ" simply means human beings. "Having faith" means they actually place their trust in it. "Without carping" means they aim no grudging fault-finding at me — at the supreme teacher, at Vāsudeva. People like that, too, are set free from action: from what goes by the names dharma and adharma.
Close to the Sanskrit
That which — this view of mine, namely 'action is to be done' — has been stated together with its proof, that is so —
Those who — 'my', that is, mine, this considered teaching — constantly anutiṣṭhanti, that is, follow it; mānavāḥ, that is, human beings; śraddhāvantaḥ, that is, placing their trust; anasūyantaḥ, that is, not directing any carping toward me, the supreme teacher, Vāsudeva — they too, being such, are released from actions, from those named dharma and adharma.