The implied information is that Jesus is not alone in his judgment. Alternate translation: "I am not alone in how I judge" or "I do not judge alone" (See: [[rc://en/ta/man/jit/figs-explicit]])
This is an important title for God. If your language must state whose Father this is, you could say "my Father" since Jesus switches to that in the following verses. (See: [[rc://en/ta/man/jit/guidelines-sonofgodprinciples]])