I don't think there is any job that needs daily worthiness to receive guidance from the Holy Spirit more than a teacher. A teacher needs inspiration in all his/her communications with students, both past as well as present. This is necessary in order to communicate accurately, without misunderstanding, and to do it in a manner that will be accepted and remembered in the best light.
It is monumentally difficult to always have just the right answer, keep all things in mind about the student and what is and will be going on. There are so many things to balance and keep in remembrance, that it is humanly impossible for a mere mortal to do well without help.
I have found that when I keep myself worthy of God's guidance, things come together better, students accept and understand better, and we enjoy each other better. Things that I never thought of or planned serendipitously mesh or blend together for a much better experience than I could ever have planned on my own. When I get myself in tune with Him and do all I can to further His will, I become a much better teacher. The resulting feelings bring peace and appreciation for that help!