Abandon all varieties of religion and just surrender unto Me.
I shall deliver you from all sinful reactions.
Do not fear.
In this verse, Krishna tells Arjuna to forget about everything he had just learned. This sounds quite funny if you think about it, because Arjuna learned quite a lot, and now he is being asked to abandon all of them and just simply surrender to Krishna.
It may seem funny, but there is a perfectly good reason why Krishna ends his discussion with Arjuna with this statement. It's because the surrender to Krishna out of love and devotion will naturally produce the desire to follow Him. This surrender will lead to the obedience towards the religion of Krishna!
When you surrender or submit to someone, like a king for example, it means that you subject yourself to that king's laws. At the same time, when you submit to Krishna, you subject yourself to his laws. You cannot surrender to someone and not devote yourself to him. Because if you don't devote yourself to him, then that is not complete surrender.
Therefore, surrender to Krishna, and by His grace, He will give you the love and devotion to obey Him. Forget about everything, just surrender to Him, and he will see to the rest.
It all begins with surrender, and obedience will follow.