If Jesus is God, then why in John 5:30 did Jesus tell his followers that he can't do a single thing of his own initiative?

Jesus was fulfilling his ministry in its entirety as a man. Galatians 4:4 tells us that Jesus was born and operated under the mosaic law. As such, he was subject to all of it’s ordinances, such as circumcision (Gen. 17:10) and not eating pork (Lev. 11:7); and he fulfilled his ministry by emptying himself in servitude even to the point of death on a cross (Phil. 2:5-8). Since he was sent by the Father (John 5:37, 8:28), under obligation to uphold the law (which required complete dependence upon the Father), and had emptied himself and was working in cooperation with limitations, he would naturally do nothing of his own initiative.