We all know it and yet we tend to ignore the old adage: seek and you shall find. In Parsha Balak, we see that adage clearly demonstrated. In turn, the parsha reminds us that whereas Hashem always has our best interests at heart, and tries to steer us down the correct path, if we are dead-set to follow a different path, He will enable us to do so.
The parsha starts with Balak dispatching messengers from both Midiyan and Moav to Bilaam. These envoys are tasked with inviting Bilaam to Moav to curse Bnai Yisroel. As pointed out in Midrash, Balak and Bilaam were united by a shared hatred of Bnai Yisroel, and needed each other to achieve their common end; Balak was skilled at locating opportune places for witchcraft/magic and Bilaam was adept at using speech rooted in tumah to bless or curse. United by their common interest, Balak and Bilaam formed an allegiance.
It is important to note that this common interest was irrational. Balak knew that Hashem had forbidden Bnai Yisroel from attacking Moav, and in turn knew that his country was safe from attack. Similarly, Bilaam knew that Hashem Himself protects and indeed blesses Bnai Yisroel, and should therefore have surmised that any attempt to curse Hashem's people would lead to his own downfall. In the case of both Balak and Bilaam then, we see that their objective was predicated on finding an excuse for acting the way that they chose.
By extension, when one's judgement is clouded by hatred or other negative forces (greed, jealousy, ego, etc.), one will persist in taking an ill-fated course of action. In the face of both the evident obstacles that Hashem put in the path of these two rashaim (the strict prohibition, the she-donkey, the failure of the attempts to curse) and the subtle precursors to failure (the messengers from Midiyan departed), they continued on their merry way to self-destruction. In effect, they were so strengthened by their shared resolve that their perception of the events they encountered became skewed in their favour.
Often when we taking the wrong course, we similarly strengthen our resolve by surrounding ourselves with those who share our opinion. In turn, by having the words of our cronies to goad us on, we act in ways that we should not. Indeed, we are all familiar with the ill effects created by crowd mentality, xenophobia, racism, anti-semitism, etc. etc. We can, in turn, appreciate the utmost importance that words hold, and how careful we must be in terms of avoiding exposure to speech that could sway us away from Hashem.
Along those lines, I would like to conclude with another Midrash, namely that a yid must constantly be asking Hashem to take him down the right path. All to often, we find ourselves going a particular direction because we concentrate on the fact that Hashem ultimately has our best interests at heart. We consequently create our own suffering, because we fail to ask Hashem to guide us correctly and therefore ending up taking a wrong turn off the correct path. We must constantly beseech Hashem to make us cognizant of the correct words and action at all times. Only then can we rest assured that the path we are taking is indeed the righteous one, the one that will result in our spiritual betterment.