Q:

What is the purpose of issuing laws/regulations without penalty?

At the beginning of November, Romanian government approved significant fiscal changes:

The Government passed the highly criticized measure of transferring
  most social contributions from the employers to the employees

Since most labor contracts are negotiated using the salary before taxes, a direct effect of these changes is smaller net income for most employees, unless the labor contract is renegotiated. 
According to this article, the Government tried to tackle this issue by forcing employers to renegotiate labor contracts:

Initiating collective negotiations in companies where no collective
  labor agreement has been concluded will be mandatory for the
  implementation of the new amendments to the Tax Code, according to a
  Government document.
However, the document doesn’t provide separate sanctions for failure
  to comply with this obligation.

Side note: Some argued [citation needed] that forcing private companies to operate salary changes not related to minimum wage is not constitutional.
This is just an example of a law or rule that does not specify the penalty/punishment for not obeying it and I feel there are many such examples all over the world.
Question: What is the purpose of issuing laws without penalty?
Why would someone consider obeying it if there is no penalty?

A:

Question: What is the purpose of issuing laws without penalty?
Why would someone consider obeying it if there is no penalty?

Laws without penalties are actually rather common. Thinking of laws in the narrow frame of the criminal law model where if you do what the law prohibits there is a punishment in terms of a fine or incarceration ignores the fact that there are many other kinds of laws which are more subtle.
To Clarify Standards For People Who Are Self-Motivated By Duty and Culture To Obey The Law
One purpose of a law without a penalty is to establish and clarify proper conduct which is directed at a group of people (e.g. judges, law enforcement officers, civil servants, people who are civic minded) who see it as their business to follow and apply the law and do so out of a sense of duty.
For example, there is no practical punishment for a judge who rules in favor of someone who the judge believes is lying and against someone who the judge believes is telling the truth by stating that the judge believes the liar is telling the truth. We trust the judge to be sincere in ruling on the evidence even if there is no practical way to prove that the judge really is sincere. And, usually judges do that, in part, because they have no reason to prefer breaking the law to not breaking the law, and in part, because they were carefully selected for their job for their integrity.
Similarly, in the U.S., law enforcement officers are immune from civil or criminal liability for exercising discretion not to enforce the law even if they could easily have done so. But, in practice, overzealous law enforcement is a much bigger problem in real life than law enforcement officers who ignore crimes out of indifference. Again, their sense of duty and purpose in their career causes them to fulfill a socially accepted role. Cultural norms, rather than laws that one can be punished for violating lead to compliance.
Laws against discrimination in hiring are a less pure case, but demonstrate the same idea in the private employment market. In practice, it is virtually impossible for an individual job applicant to prove discrimination in hiring for a job where there are a large number of applicants, and it is quite difficult to prove even for a public agency using "tester" applicants and statistical evidence in the absence of an outright admission of the employer that the employer is discriminating in hiring. But, laws prohibiting discrimination in hiring have nonetheless had a profound effect on the way employers act in hiring employees, because most employers have a general policy of obeying the law and because the law has changed the corporate culture and norms concerning what hiring practices are acceptable, in general.
To Create A Right That Can Be Specifically Enforced Even If There Is No Penalty For Violating It In The Absence Of An Order To Comply
Often, a law that doesn't have a "penalty" attached to it, can nonetheless be specifically enforced. Thus, while an employer might not face a fine or imprisonment for not renegotiating, a court might order an employer to renegotiate, or might declare that a contract that was not renegotiated is no longer enforceable on the part of the party that refused to enter into renegotiation talks.
To Clarify The Legal Effect Of Language In Other Laws Or Contracts Or Of Particular Kinds Of Conduct
Many laws are also passed that instead of having a "penalty" per se are used to interpret other laws or agreements or situations.
For example, a law might state that you are married if you do X, Y and Z, and this allows people to know if they are governed by the laws applicable to married people, or the laws applicable to unmarried people.
Or, a law might state that if you use certain words such as "or my successors and assigns" in language transferring property, that you have created a permanent and transferrable property right, while if you do not use that language, you have only created a temporary right of the person receiving the property to use it for the rest of their life that is not transferrable. These kinds of laws are sometimes known as "rules of the road" statutes where the exact form of the rule is less important than having a clear standard for classifying a situation as belonging to one legal category or another.
A similar law would be the definition of a "minor" as, for example, someone who is eighteen years old as shown by their birth certificate. There are consequences to being a minor or not being a minor that are legally relevant, but they aren't necessarily "penalties" in the strict sense of the word.
To Clarify Undefined Rights
There is a law that says who inherits from someone who dies without a will, something that would otherwise be undefined. The law establishes rights and there may be legal consequences for disregarding those rights, but it isn't really a law with a penalty involved for violating it in the same way that there is for violating a penal law such as a law that establishes a penalty for drunk driving.
To Facilitate Collective Action
Another purpose of laws without penalties is to facilitate collective action.
For example, suppose that you pass a law declaring that December 9, 2017 is National Donut Day, and there are no penalties or enforcement mechanisms of any kind associated with that law. It is still likely that the existence of that law will cause donut vendors across the nation to offer special deals and promotions of their donuts at the same time and will cause media outlets to discuss National Donut Day, even though there are no penalties involved, in a way that would not have happened if a law hadn't existed to coordinate the efforts of the people promoting donut awareness.
To Influence Public Opinion And The Perceptions Of The Parties
In the Romanian case, it nudges employers who don't want to be perceived as anti-labor to the point of even violating a law (even if the law has no penalty) to renegotiate because ignoring the law will impact the course of the negotiations as perceived by their labor counter-parties, and the reputation of the company. Ignoring the law will probably give rise to publicity and usually when you break a law, even if it has no penalty, the publicity consequences of breaking it are bad. XYZ Corp. violates national labor laws is not a headline that most CEOs want to see in the papers.
To Relieve Someone Who Complies Of Obligations To Third-Parties That Would Otherwise Exist
Another possible impact of a law, even without penalties, is to relieve someone subject to the law from any penalty for taking the actions that the law requires.
For example, if a corporate officer renegotiated a labor contract that otherwise wasn't up for renegotiation on terms less favorable to the company in the absence of such a law, the shareholders might have the right to sue the company or its officers for the corporate officer's indifference to their interests. But, if the corporate officers were required by law to do so, even if there was no penalty for not doing so, the shareholders could probably not sue the corporate officer for cutting this kind of deal.
Similarly, suppose that the law states that an employee has a right to help someone in a manner unrelated to his job in an emergency. This might define an ambiguity in an employment contract or deprive an employer of the ability to punish the employee for doing so, even if this is not exactly a penalty.
For Political Symbolism
Sometimes laws that are found to be unconstitutional or are substantively repealed are kept on the books for symbolic political purposes.
For example, in Colorado, adultery is illegal and remains in the criminal code, but there is no penalty in the criminal code for violating that section of the criminal code, it is actually a crime in Colorado to bring a civil action alleging adultery, and adultery is not a ground for divorce or a factor that can be considered in a divorce proceeding. But, legislators felt that actually repealing the adultery law as opposed to retaining a statute that says it is illegal with no penalty, would appear to condone conduct that is overwhelmingly viewed as immoral, at least.
The fact that adultery is illegal in Colorado also prevents it from becoming a protected right. For example, an employer could fire an employee for adultery, or refuse to hire or promote someone because they have committed adultery, without violating Colorado law. Also, this illegality of adultery, even without penalty, validates the fact that in a defamation action, a knowingly false statement that someone has committed adultery is actionable and can provide a basis for an award of money damages for harm to a person's reputation.
Several U.S. states have kept laws establishing religious tests in their state constitutions, even though those provisions have been held to be unconstitutional and unenforceable, as a symbolic way to show support for the religious majority.

