From Knoxville:

Take Pellissippi Parkway to Oak Ridge, where it becomes Illinois Avenue. Bear right onto Lafayette Avenue (at the Y-12 Credit Union building).  Travel 1.4 miles to the traffic signal at Gettysburg Avenue, where you will turn left. Travel .2 miles and Grace Lutheran is on your left.

From Clinton:

Take TN-61 to Oak Ridge, where it becomes the Oak Ridge Turnpike.  Turn left at traffic signal #6 (Lafayette Avenue).  Travel .4 miles to the traffic signal at Gettysburg Avenue, where you will turn right. Travel .2 miles and Grace Lutheran is on your left

For driving directions, follow this link to make a custom driving map from your house.