I found this sentence in the lyrics of a song:

> 振り返れ **ば** もう戻れない **から**

I don't understand the context and the function of から placed in this sentence.

The song is this:

<http://m.kget.jp/lyric.php?song=260055>
CC BY-SA 4.0
2020-11-19T01:53:23.413
82691
2020-11-19T01:53:23.413
39362
question
song-lyrics conditionals particle-から japanese-to-english context
What is the function of から in this sentence?