SB 11.29.23

eṣa te ’bhihitaḥ kṛtsno
 brahma-vādasya saṅgrahaḥ
samāsa-vyāsa-vidhinā
 devānām api durgamaḥ
Synonyms: 
eṣaḥ — this; te — unto you; abhihitaḥ — has been described; kṛtsnaḥ — completely; brahma-vādasya — of the science of the Absolute Truth; saṅgrahaḥ — the survey; samāsa — in brief; vyāsa — in detail; vidhinā — by both means; devānām — for the demigods; api — even; durgamaḥ — inaccessible.
Translation: 
Thus have I related to you — both in brief and in detail — a complete survey of the science of the Absolute Truth. Even for the demigods, this science is very difficult to comprehend.
Purport: 

The word devānām indicates those living beings in the mode of goodness (such as demigods, saints and pious philosophers) who nevertheless cannot understand the Absolute Truth because they lack full surrender to the Personality of Godhead.