Question on the i-form

[CaptainThunder]

Basically, I've run into the i-form a few times, seemingly standing alone, and I'm not really sure why it was chosen over other forms. Here are two examples I've seen recently, both from song lyrics:

"君がくれた言葉ひとつ戸惑いは消え去り。"

"誰かが言った「幸せになるため産まれ、そして誰かを幸せにするためいきていくんだ」"

In the above sentences, I'm curious as to why the words in red were conjugated to the i-form. The dictionary form seems adequate to me in the first sentence; I'm less sure about the second sentence, but I would have guessed that it would have been in either the te-form or the dictionary form.

Whenever I see the i-form, it is usually attached to something like -masu or -tai, so these situations where it stands alone are confusing to me. Would any of our resident experts like to shed light on the uses of the form in the above examples, and perhaps explain how those uses are connected?

Thanks.

[MMM]

This is common in literature.