A biblical argument for the liberating power of truth is that if you live in (listen to, obey) the Word of God, then you will know the truth, and the truth will set you free (John 8:31). If you commit sin, then you will be a slave to sin (8:34), but if you live in the Word of God, then you will no longer be a slave to sin, because you will live in truth, and the truth will set you free.
It may perhaps be argued to the contrary, however, that the discovery of truth may in some cases be very distressing and painful to us, and that we may experience the discovery of truth as oppressive, rather than liberating. Our discovery of a troubling, disquieting, or disturbing truth may in some cases lead us to regret having discovered it. We may regret having allowed ourselves to be deceived or misled by someone we trusted. We may blame ourselves or feel humiliated for having mistakenly trusted someone we thought we could trust.
Discovering the truth may also in some cases lead us to become more aware of our being used and manipulated by someone or our being subjugated and oppressed by something beyond our control. In such cases, we may not perceive this awareness as liberating. We may rather perceive it as painful, discouraging, heartbreaking, or overwhelming.
The truth may not set us free if the truth we are compelled to accept is a conventional, (inter)subjective, dogmatic, or propagandistic truth that we may not necessarily accept as our own. What is (inter)subjectively or conventionally true for and assumed by others (for example, that personal success is defined by the accumulation of money, prestige, and power) may not necessarily be true for and assumed by us, and we may therefore not feel liberated by being compelled to accept such (inter)subjective truths and conventional assumptions.
Having always to tell the truth may also not set us free if there are cases in which it is morally better not to tell the truth (or at least not the whole truth). Having to always tell the (whole) truth may hinder our moral freedom if we encounter cases in which it is morally better not to tell the (whole) truth.
The truth may also not set us free if whatever we thought was true turns out to be false. Some purported or supposed truths may not turn out to be actual truths. Some statements that appear to be true at first glance may not turn out to be true on final analysis.
The truth may not always set us free if freedom is defined merely as the freedom to act in whatever way we choose, regardless of the moral and practical consequences of our actions. However, freedom to act in whatever way we choose may not be true moral freedom, which may involve the freedom to act morally and responsibly, with regard for the moral and practical consequences of our actions.
In some cases, discovering the truth may lead to us to recognize that we have many (moral, social, professional, and public) obligations to fulfill in order to respond appropriately to knowing the truth. While our moral freedom may be defined by our awareness of, and compliance with, our moral obligations, we may sometimes be intimidated, disheartened, or dismayed by the number, extent, and stringency of those obligations. We may not always feel as if we are freer after discovering the truth than we were before discovering the truth and recognizing the number and extent of our obligations.
There may, of course, be many counter-arguments (some more religiously dogmatic or fundamentalist than others) to these arguments against the liberating power of truth. The counter-argument may be made, for example, that discovering the truth is always better than not discovering it, regardless of the pain or suffering that discovering the truth may sometimes involve, because only by discovering the truth can we become morally and spiritually free. Another such argument is that knowing what is morally right may be a condition for acting morally (e.g. the "knowledge is virtue" argument). Another such argument is that only by being committed to truth and justice can we promote social harmony and well-being.