The Difference between Belief and Practice

Areopagus with the Acropolis of Athens in the ...
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Paul is brought before the city leaders in Athens and preaches the good news of Jesus Christ. In response,

“Some of the people became followers of Paul and believed. Among them was Dionysius, a member of the Areopagus, also a woman named Damaris, and a number of others.” Acts 17:34

The text clearly states that people “became followers of Paul and believed.” While the example of a deeply committed Christian is worth following, I would have first considered that they became followers of Jesus. Is there a difference between belief and practice? Can you help me make sense of this verse of scripture?