1) X and Y are the same object, if X has every property that Y has, and Y has every property that X has.
2) Christ has a metaphysical property that his Father does not have (his humanity).
3) Christ's Father has a metaphysical property that his Son does not have (the Father is innascible).
4) Therefore, Christ is not the same object (i.e., person) as his Father.
The argument is presented from the perspective of a Trinitarian. The doctrine of the Trinity claims that Christ and his Father are the same God, but they are not hypostatically identical, that is, Christ and his Father are not the same in a personal sense.