The objective of Bhagavad Gita is to remove delusion.
Bhagavan Satya Sai explains nicely which is recorded in book Sai Gita, page 23 which you can read here
Have a clear understanding of the Gita in your heart. What is the
essence of the Gita teachings? Some say that it is the path of service
and action, and others say that it is the path of love and devotion.
Still others say that it is the path of knowledge and wisdom. But
these are all partial truths. The Gita starts with a verse whose first
word is dharma, which means duty or right action. The concluding verse
of the Gita ends with the word 'my'. When these words are taken
together they become 'my duty' or 'my work'. That summarizes the whole
teaching of the Gita. It means you should perform your prescribed duty
to the very limits of the human capacity for excellence and
perfection, doing the work that is appropriate to your stage of life.
When you are a student study your lessons well. When you are a
householder perform your work and family responsibilities properly.
When you are retired perform the duties appropriate to that stage, and
if you have renounced the world to engage yourself in contemplation of
the reality, then stick to that path. When you follow your prescribed
duty in the very best way possible, discharging your duty sincerely
and conscientiously, then there will be no confusion or misery. Arjuna
had to perform his duty on the battlefield. His calling was to be a
warrior and to combat evil and protect the good. But, when he saw his
friends and relations arrayed on both sides of the battlefield, he
forgot his strong resolve to fight for right, the fight for which he
had been preparing for so long. He became full of attachments and
delusion, and threw down his bow. He abandoned his duty and became
miserable. Krishna taught Arjuna how to free himself from despair by
adhering to his prescribed duty. Krishna taught Arjuna the truth of
the immortal self, and showed him that his duty was to follow the
inner promptings of the Lord, who was enshrined in his heart. When
Krishna finished his teachings, he asked Arjuna, "Have your
attachments and delusions disappeared?" Arjuna picked up his bow and
answered, "My despair has completely vanished. All my delusion is now
gone. I will do as you command!" As long as you have delusion you will
be in a state of bondage. When you suffer from delusion and
infatuation, liberation is impossible. Liberation has nothing to do
with worldly pleasures. It is not an air-conditioned car or a
comfortable life. It is the complete destruction of delusion. i.It is
the extinction of all worldly attachments, the incineration of all
selfish desires. From now on, do your duty to perfection and become
ideals for mankind. Apply the teachings of the Gita in your daily life
and be blessed with grace. Many of you are just wasting your time.
Start today to reform yourself. Don't waste time. Time is God. Every
day spend some time on these holy teachings and contemplate their
inner meaning. Once they are understood, put them into practice. Only
in this way will you be able to attain a sacred life, a life of purity
and perfection, which is the mark of a true human being.
This is the most widely appreciated teaching of Gita appreciated by all classes of people.