Commentary for Gittin 110:16

Fears: Is concerned to see the outcome; such that if I do this no misfortune should arise from it.

Happy is the man who always fears: In the chapter [entitled] HaRoeh, we say [that Rabbi Yishmael, son of Rabbi Yose] saw that a certain man was afraid. He said to him, "You are a sinner, as it is written, 'The sinners in Zion are afraid.'" But [the other] challenged from the verse here; and it was established to be about matters of Torah, such that he worries to not forget his studies and always reviews his learning. And here too, he brings [this verse] about these events in which they trusted in their great wealth and tranquility to embarrass Bar Kamtza and to stand up to Caesar's daughter, whereas they should have been afraid and worried about punishment. And that is not similar to someone who is afraid for nothing.

A shaft from a chariot (rispak): The siding of a women's chariot, which is called, rituga, in the language of Ashkenaz (German). And it is like a type of wagon. For we say in [the chapter entitled] Oto veEt Beno (Chullin 79a), "If you bring me mules [attached] to a wagon (rispak)."

Kamtza and bar Kamtza: Such was the name of two Jews.