Bhagavad Gita Verse 11, Chapter 15

yatanto yoginashchainam pashyantyaatmanyavasthitam |
yatantopyakritaatmaano nainam pashyantyachetasaha || 11 ||
 
Those striving yogis realize this as residing within the self. But those with an unprepared mind, though striving, do not see this, devoid of knowledge.
 
yatantaha : those who are striving
yoginaha : yogis
cha : and
enam : this
pashyanti : realize
aatmani : within the self
avasthitam : residing
yatantaha : striving
api : though
akritaatmaanaha : unprepared mind
na : not
enam : this
pashyanti : see
achetasaha : devoid of knowledge
 
In any difficult endeavour, there are three kinds of people. There are the vast majority who are not interested the least bit in striving for the goal, and blissfully accept their state as a given. There are a small number of people who are putting in great effort or dedication, but not obtaining the desired outcome. A select few, however, are able to channelize their efforts in the right direction and get what they want.
 
Shri Krishna called the vast majority of people, the first category, stuck in the cycle of Prakriti "deluded" in the last shloka. Here, he says that it is the preparation of mind that determines whether or not the efforts taken by yogis - those who are striving for liberation - have a chance of success. One without a prepared mind is termed as "akritaatmaanaha" in this shloka. So then, those of us who are aiming for liberation would not like our striving to be in vain. What should we do?
 
We need to understand what Shri Krishna means by purifying our mind. There are two aspects to this. The first aspect is the degree of selfish desires. Unless we have followed the path of karma yoga and bhakti yoga as laid out in the earlier portions of the Gita, our mind will not be able to properly absorb any scriptural teaching whatsoever. The second aspect is the type of knowledge we are trying to absorb and the method of doing so. A systematic understanding of the scriptures under the guidance of a teacher is the only way. One who does not follow a systematic process of imbibing knowledge is termed "achetasaha", devoid of wisdom.
 
The topic of the jeeva is concluded in this shloka. with the message that only those with a pure mind and systematic study will truly understand the nature of the jeeva as the eternal essence as though limited by its upaadhis or conditionings.