A.T. Robertson Commentary John 4:13

"Jesus answered and said unto her, Every one that drinketh of this water shall thirst again:" — John 4:13 (ASV)

Every one that drinketh (πας ο πινων). Present active articular participle with πας, parallel to the indefinite relative with the second aorist active subjunctive (ος αν πιη) in verse 14. With this difference in the tenses used (πινων, keep on drinking, πιη, once for all). Note εκ and the ablative both times, out of the water. Jesus pointed to the well ("this water").