Among his works are Pi Yesharim (Frankfort, 1702), kabbalistic comments to the word bereshit ("in the beginning"); and Sha'ar Naftali, poems and piyyutim (Bruenn, 1757). Several works are still in manuscript. R. Naphtali was one of the important halakhic authorities of his generation and one of the greatest kabbalists of Poland. His image persisted in the memory of the people, and many legends and wondrous tales about him circulated for many generations. He conducted his rabbinate high-handedly and as a result met much opposition from the leaders of the communities, which was apparently the cause of his frequent wanderings. Despite this he had a sensitive soul which found expression in his poems, piyyutim, and prayers which have been published in various places. His well-known ethical will (Berlin 1729) contains profound thoughts and moral instruction and some see in it one of the first sparks of practical Hasidism.