Alpha and Lambda In Alexandrinus
The letters in and alphabet are not always easy to distinguish. Take the u and v in English. A "u" with an only slightly rounded bottom can look quite a bit like a "v" with a slightly rounded bottom. And when you get into cursive, it can become even harder.
In Greek writing there are certain letter patterns that lend themselves to confusion like this. In uncial handwriting a commonly confusing couple of letters are α and λ. For example, look at this image from Alexandrinus:
The text is as follows:
γε ουδεν ημας ρυσεται εκ της αιωνιου κολασεως· εαν παρα
Once again we have a text from 2 Clement (6:7). Look in the middle of the second line. Note that the α and λ in κολασεως are very similar. The difference is easier to see if you zoom in, but keep in mind that was not a luxury for the scribes. And what if the letter was smudged a little or some of the ink on the left tail of the alpha faded? It is things like this that made being a scribe difficult and caused many a variant to come into the tradition.
Of course a smart scribe would know that κολλσεως and κοαασεως are not real words and that clearly the scribe mean κολασεως. But how many times did a scribe clean up a text he was reading that didn’t actually need to be changed? There’s another source of our variants...