Was it fresh, uncooked beef? If so, it would be fine. Just make sure you heat it thoroughly.
Like Tilly, I'd have it cold. Can't stand over cooked beef.
Texture, flavour, vitamins and calorific value and so on might suffer, but you can go on and on reheating food (to above boiling point for a few minutes), so as not waste it. I cooked far too much quill pasta a week or so ago and reheated the leftovers 4 times, but I could have frozen instead.