What is "al-isr" (the burden/shackle), and did it exist before the Messenger Muhammad, may God bless him and grant him peace?

What is meant by "the burden" (al-isra): The severe laws and difficult obligations that were imposed upon the Children of Israel, which Allah removed from the nation of Muhammad (peace be upon him) as an honor for them. So, the meaning of "and relieves them of their burden and the shackles that were upon them" is: the strictures and difficult obligations that were in the religion of the Children of Israel.

Indeed, Muslim narrated in his Sahih that the Messenger of Allah (peace be upon him) warned his Companions against saying what the People of the Two Books said: "We hear and we disobey," and commanded them to say: "We hear and we obey." So, Allah the Almighty revealed: "Allah does not burden a soul beyond its capacity." Ibn Taymiyyah said that the burdens are the severe obligations, and the shackles are the severe prohibitions.