"The great Zen master Rinzai, in order to take his students' attention away from time, would often raise his finger and slowly ask: "What, at this moment, is lacking?" A powerful question that does not require an answer on the level of the mind. It is designed to take your attention deeply into the Now. A similar question in the Zen tradition is this: "If not now, when?" p. 38"
January 1, 1970
https://en.wikiquote.org/wiki/Eckhart_Tolle