Since this is the philosophy stack exchange site, I will answer somewhat from a scholarly philosophical context. The answer, I think, is that it depends on what philosophical context you choose to think from.
Some possibilities:
The meaning of life is just to be alive. It is so plain and so obvious and so simple. And yet, everybody rushes around in a great panic as if it were necessary to achieve something beyond themselves. - Alan Watts
So we spend a lot of time worrying about what we ought to do and what we ought to not do - following our current whims and beliefs about what is right and what is wrong.
Driven to act, it is often our ego dictating what we ought do or not do. If we believe x, are we morally bound to act upon x, and what must we do?
Often acting from this context, we will end up doing more harm than good, and become fixed on our beliefs, certain that what we are doing is right. One need look no further than Twitter to see how dangerous that can be.
Act only according to that maxim by which you can at the same time will that it should become a universal law. - Immanuel Kant
Do you believe that your position on abortion is something that you believe should be a universal law? Do you think it is an unquestionably good position for all? Does it align with a pre-existing universal truth? (For example, Never Lie).
If so, you are, for the most part, obligated to act in accordance with your position.
Kant is too heavy to capture in a paragraph, but the above isn't a terrible intro. I think Kant is limited and deliberately ignores realities that he doesn't like, but for the most part, you won't damage yourself following his philosophy.
What destroys a man more quickly", he asks, "than to work, think, and feel without inner necessity, without any deep personal desire, without pleasure—as a mere automaton of “duty”?" - Friedrich Nietszche
When obligated to act there is no creative, joyful purpose in one's actions. Are we not just slaves to some master (internal or external)? We are bound and thrust into our action, and as it is our duty, we will die defending it. The people who followed Hitler's dictates often thought they were in the right. They believed in the cruelty suggested by their master, and believed they had a duty to follow that master. It is easy to blindly obey under the guise of loyalty.
Love God and do. what you will - St. Augustine
As long as your cause is square with your God, then do it joyfully.
Ultimately, I think my position lies somewhere in the middle. While it is fine to act in accordance with a spiritual guide, and "do what you will", if you want to make a difference, you won't get far that way. You won't always feel like it, and your emotions will be conflicted, and for myself, the only way I will ever have the discipline to do anything is to set up my actions as a matter of my own integrity, and force myself to act no matter whether I feel like it or not.
But at the same time, the internal pull to a particular cause can be dangerous, because coming from the wrong place, it can harm and ignore others, and even produce unexpected and undesirable results.
I think it is essential to act on that which you choose to act on, not from obligation, but from a place of creativity and honesty. For example, it is not, "I think x about abortion, so I must do y". It is more like, "Given I think x about abortion, what could I do that would make a difference? What is the intention behind my opinion? Do I think that all people should be treated equally? Or is it that I want people to experience being taken care of? What can I do to fulfill on that? Do I want to do anything? Does it light me up?"
It is essential to examine ones own motives. As Werner Erhard said, (paraphrasing):
I am distrustful of all motives, especially my own.
