What is your opinion on the saying, "From the fingers of your hands, I know your personality," and is this saying considered to be a form of divination and palmistry?

What is mentioned in the question is not divination or fortune-telling, for the absolute unseen is known only to Allah, and whoever claims otherwise is a liar. Rather, it is a form of firasah, which is "inferring character from physical appearance," like observing the relationship between physical and moral traits. Firasah can be right or wrong, and it is not a definitive science, nor should its accuracy be asserted with certainty. For morals change with the change of companionship and adherence to the Sharia, and the characteristics of a single hand may vary, and the circumstances of its owners differ in terms of age, gender, and disabilities.