If I were offered a position that was projected to be fruitful

If I were offered a position that was projected to be fruitful and sustainable with another firm, I would take it. This happens every day in the business world. Many employees look for a job that can be or will be more beneficial to them financially, emotionally, or for any other personal reasons they have deemed necessary to look for another job. In a legal sense, the departure of an employee going to a competing firm is a delegate situation. The firm in which you are leaving has an obligation to protect their client’s interests wholly. That is why there are non-compete agreements, non-disclosure agreements, and confidentiality agreements. However, I think most importantly, it is where a person’s character and integrity come to play. As long as you remain loyal and do your job, while you are there, in the best interests of the company, you have fulfilled your duties to that company.
You may not have to disclose where you are actually going to work afterwards, but you should abide by the guidelines laid out in the employment handbook/agreement that most, if not all, employers have in place. This is usually at least a two-week notice, but you should always check with the guidelines and handle the situation professionally. “A paralegal must adhere strictly to the accepted standards of legal ethics and to the general principles of proper conduct.” NALA (2001).
I think Matthew 7:12 (ESV) most closely relates to how you should treat the departure of an employee/employer relationship: “So whatever you wish that others would do to you, do also to them, for this is the Law and the Prophets.” If you do right by your employer, while employed, I don’t think there is much more that can be demanded or needed from you.