Is it enough to just listen to the bible?

Yes and no. I love to frustrate people with such an answer!

Yes, if you take it very slowly and discuss the details with a group over an extended period of time. Even better is if you listen to an expert (preacher/teacher) explaining the sense of the text you have just listened to. This is how it was done in the book of Nehemiah

"...the Levites, helped the people to understand the Law, while the people remained in their places. 8 They read from the book, from the Law of God, clearly, and they gave the sense, so that the people understood the reading." - Nehemiah 8:7-8

And no, because there is too much detail in most of the bible for you to pick up through listening, even just careful listening.

But again, yes, because you can get the main ideas pretty easily from listening, especially if you have the Spirit helping you to understand.

Whatever you do, listen or read, don't take your daily bread lightly.  Consider how you do everything and do it deliberately, with care, with love, and with the most glory to God in mind.