Link to purport by A C Bhaktivedanta Swami Srila Prabhupada

Transcript of Bhakti-Shastri class on this verse by Chaitanya Charan

Now the next verse will give Gyan Sadhana 

Bg 18.50

siddhiṁ prāpto yathā brahma
tathāpnoti nibodha me
samāsenaiva kaunteya
niṣṭhā jñānasya yā parā

Synonyms: 

siddhim — perfection; prāptaḥ — achieving; yathā — as; brahma — the Supreme; tathā — so; āpnoti — one achieves; nibodha — try to understand; me — from Me; samāsena — summarily; eva — certainly; kaunteya — O son of Kuntī; niṣṭhā — the stage; jñānasya — of knowledge; yā — which; parā — transcendental.

Translation: 

O son of Kuntī, learn from Me how one who has achieved this perfection can attain to the supreme perfectional stage, Brahman, the stage of highest knowledge, by acting in the way I shall now summarize.

siddhiṁ prāpto yathā brahma, how one can attain perfection, brahma, is a generic name referring to the Absolute Truth, 

tathāpnoti nibodha me, bodh means to understand, nibodha, try to understand

samāsenaiva kaunteya, in summary I will tell

niṣṭhā jñānasya yā parā, by the process of Gyana one can gradually rise to the transcendental level.

End of transcription.