This is what subject-verb agreement is: <em>I walk</em> versus <em>He walks</em>
When you put something between the subject (I/he) and the verb (walk(s)), the verb does not change. <em> </em><em>I slowly walk. </em><em>He quickly walks.</em>
Sinners have little left to mess up after they sin of course. It is almost like treading on “thin ice”. Like also meaning whatever they do next is the last straw.