John Cassian
Catena Aurea · Matthäusevangelium 6
But when ye pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking. Be ye not therefore like unto them: for your Father knoweth what things ye have need of, before ye ask Him.
(Collat. ix. 36.) We should indeed pray often, but in short form, lest if we be long in our prayers, the enemy that lies in wait for us, might suggest something for our thoughts.