The Braisa says (Pesachim 56a, quoted as Mishnah 4:8):
תנו רבנן ששה דברים עשה חזקיה המלך על שלשה הודו לו ועל שלשה לא הודו לו גירר עצמות אביו על מטה של חבלים והודו לו [...]
The Rabbis taught: King Chizkiya did six things; regarding three did [the Sages] agree to him, and regarding three did they not agree to him. He dragged his father’s bones on a reed bed, and they agreed to him. [...]
Rashi there, in Pesachim 56a, explains why he did this:
גירר עצמות אביו - משום כפרה ולא קברו בכבוד בדרגש ומטה נאה ומפני קידוש השם שיתגנה על רשעו ויוסרו הרשעים:
“He dragged his father’s bones” - as an atonement, and he did not bury them honorably with a canopy(?) and a nice bed. This was to sanctify the Name which [Achaz] disgraced in his wickedness, and the wicked suffer.
It seems from this Rashi that Chizkiya dragging Achaz’s bones was to Achaz’s benefit, enacting some form of atonement for his sins.
But Rashi to Berachos 10b explains this Braisa differently:
גירר עצמות אביו - לפי שהיה רשע בזהו ולא נהג בו כבוד בקבורתו להוציאו כהוגן במטות זהב וכסף:
“He dragged his father’s bones” - because [Achaz] was wicked, [Chizkiya] denigrated him and did not treat him with honor in his burial, to take him out properly with beds of gold and silver.
Here Rashi sounds like he did not have the intention to benefit Achaz, but rather solely to denigrate the wicked.
Rashi uses this latter interpretation on Pesachim 47a as well:
על מטה של חבלים - דרך בזיון מפני שהיה אביו רשע וביזהו לעיני כל [...]
“On a reed mat” - in a denigrating way; since his father was wicked, he denigrated him in the eyes of all [...]
- Why does Rashi change the overall message?
- Rashi also changes what a “proper burial” would be - in Pesachim 56a he talks about a “canopy(?) and nice bed,” but in Berachos he describes “beds of gold and silver.” Is this related, in that he didn’t do certain things to benefit him and he didn’t do other things to denigrate him?