In perek 17 we have an interesting passuk which appears slightly differently in Yirmiya (2:5):
“They have gone after Hevel (nothingness), and become Hevel.” (17:15)
This passuk teaches us a vital lesson about the power of actions as Rabbi Speyer zt’l, mashgiach of Ohr Samaych, would say, “The actions which we run after and are busy with, can shift from being something we do to becoming part of who we are”. The more deeply we chase after, and busy ourselves in something, the more that thing becomes part of us. Thus, running after Hevel can begin to define the person as Hevel.