As a layperson not belonging to the Secular Franciscan Order, am I allowed to wear a Tau cross? Can I wear it with knots? Because I have not taken the same vows, I’m not sure if it’s proper for me to wear the knots.
Yes, you can wear that cross—with or without knots on the cord to which it is attached.
A few years ago, I was in Franciscan Media’s booth at the Los Angeles Religious Education Congress in Anaheim, California. That year we were giving away Tau crosses on cords. On the second day, someone complained bitterly that we should not be doing that because this person received the Tau cross only after completing the Secular Franciscan novitiate.
Although the Tau cross existed before St. Francis of Assisi, he popularized its use toward the end of his life. He also warned his friars as a general rule not to “appropriate” things. No one has exclusive rights over a certain type of cross. If you wear any type of cross, let it remind you of Jesus’ great love and also inspire loving words and actions on your part.