John Trapp on Isaiah 12:3

Ver. 3. Therefore with joy ſhall ye draw water] Joy is the juſt mans portion: and Chriſt is the never-failing fountain, whence by a lively faith he may infallibly fetch it, John 4.10, 14. & 7.37. Chriſt was much delighted with this Metaphor: ſee Joh. 1.16. Out of this Fountain only may men quench their Spiritual thirſt after Righteouſneſs. Haec ſola eſt aqua quae animas arentes, maerentes & ſqualidas reficit, & recreat. Theſe Wells of Salvation are thoſe Words of Eternal Life, John 6 68.Sanchez. the rich and precious promiſes, 2 Pet. 1.4. whereby we are made partakers of the Divine Nature, and of the Holy Spirit, which is frequently and fitly compared to water in regard of Firſt Ablution, Ezek. 36.25. Secondly, of Fructification, Job 8.11. Iſa. 35.6, 7. & 44.3, 4. And thirdly, of Refrigeration, Pſalm 42.1. Rom. 5.5. Some think the Prophet here alludeth to thoſe ſoftly-running Waters of Siloam, chap. 8. or to the Rock-water that followed them in the Wilderneſs, or to that famous Fountain, Numb. 21.16,—18. whence they drew waters with ſo much mirth and melody.