Does a 2023 tax rebate, received in 2024, need to be added into 2024 income?

What kind of tax did you get a rebate for: federal income tax? state income tax? real estate tax? another kind of tax? Do you mean that you got a refund on your 2023 federal or state income tax return?

On your 2023 federal tax return did you use itemized deductions or the standard deduction? If you used itemized deductions, did you claim a deduction for the tax that you got a rebate for in 2024?

Sometimes, but we need more information.  It depends on who paid, why they paid, and what was the tax treatment of the initial even that led to the rebate.