Commentary for Gittin 110:19

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.

Whose friend was Kamtza: His friend's name was Kamtza.

And whose enemy was bar Kamtza, etc.: It explained with this that the beginning of the destruction was on account of baseless hatred, as it is written in the first chapter of Yoma (9a), "During [the time of] the Second Temple, when they were occupied with Torah [study] and with the commandments, on account of what was it destroyed? Because they had baseless hatred, etc." And it said...

He went and brought him bar Kamtza, etc.: It was possible that this was a father and his son, and the messenger erred about them. And also that which bar Kamtza came even as he knew that he was his enemy, was because he reasoned that since his father was his friend, he certainly wants his friendship also, to make peace with him through this invitation. And it is as it is written in Eruvin (65a), "Whoever is appeased by his wine has in him the mind-set of his Creator, as it is stated (Genesis 8:21), 'And the Lord smelled the pleasing savor.'" And it is understood: One who has hatred against his fellow because he did something improper to him, and is appeased by his own wine - meaning he invited him to a drinking party that he made - has in him the mind-set of his Creator. For also the Holy One, blessed be He, was appeased to man who sinned towards Him with something that was His, since the whole world is His - as it is stated, "And the Lord smelled the savor, etc." - the pleasantness that he did His will, as the Re'em (R. Eliyahu Mizrachi) wrote. But the master of this feast did not have the mind-set of his Creator in him. So even after [bar Kamtza came by mistake, he said, "How is this; that man is the enemy, etc. And how did you err to think that I would invite you, since you are my enemy?" And he did not pay attention to any of his requests, as it concludes - until he took him with his hand and removed him by force.