premise: Besides , they were too little to go outside of the Old Briar-patch now .<br>Indeed , they were too little to go outside their nursery , which was in a clump of sweet-briar bushes in the very middle of the Old Briar - patch , and Peter felt that there they were perfectly safe .<br>`` It is n't time to worry yet , '' said Peter to little Mrs. Peter , as he saw the fright in her eyes as the shadow of Redtail passed over them .<br>`` I do n't believe in borrowing trouble .
hypothesis: They needed to grow before leaving.
reason: They were too little to leave.