This is true because you and all others are one.
What you do for others therefore you do for you.
What you fail to do for others you fail to do for your. What is good for another is good for you and what is bad for another is bad for you.
This is the most basic truth and this truth you most frequently ignore.

When you are in a relationship with another, that relationship has only one purpose. It exists as a vehicle for you to decide and to declare, to create and to express, to experience and to fulfil your highest notion of Who You Really Are.
If you really are a person who is kind and considerate, caring and sharing, compassionate and loving – then, when you are being these things with others you are giving yourself the grandest experience for which you came into this body.
This is why you took a body. Because only in the physical realm of the relative could you know yourself as these things. In the realm of the absolute you this experience of knowing is impossible.
Now if Who You Really Are is a being who does not love the Self, and who allows the self to be abused, damaged, and destroyed by others, then you will continue behaviours which allow you to experience that.
Yet if you are a person who is kind and considerate, caring and sharing, compassionate and loving, you will include your self among the people with whom you are being these things.
Indeed you will start with yourself. You will put yourself first in these matters.

Everything in life depends on what you are seeking to be.
If for instance you are seeking to be One with all others (that is if you are seeking to experience a conceptualisation you already know to be true), you will find yourself behaving in a very specific way – a way which allows you to experience and demonstrate your Oneness.
And when you do certain things as a result of this, you will not experience that you are doing something for someone else, but rather, that you are doing it for your Self.
The same will be true for no matter what you are seeking to be. If you are seeking to be love, you will be doing loving things with others. NOT FOR OTHERS BUT WITH OTHERS.
Not for – but with others. So that you can actualise and experience your grandest idea about your self and Who You Really Are.
In this sense it is impossible to do anything for another, for every act of yours is just that – an act. That is creating and playing a role. You are a human being. And what you are being is decided and chosen by you.
Shakespeare said, “All the world’s a stage, and the people, the players.”
He also said,” To be or not to be, that is the question.”
And,” To thine own Self be true, and it must follow, as the night follows day, thou canst then be false to any man.”

When you are true to your Self, when you do not betray your Self, then when it ‘looks like’ you are “giving’ you will know you are actually “receiving”. You are literally giving yourself back to your Self.
You cannot truly ‘give’ to another, for the simple reason that there is no ‘other’.
If we are all One, then there is only You.