I will pour water... — The latter words of the verse interpret the former. It is not the union of material or spiritual blessings, but first the symbol, and then the reality. The “thirst” is that of Psalms 42:1; John 4:13-14. In the promise of the Spirit we have an echo of Joel 2:28.
Related Commentaries of Isaiah 44:3
Isaiah 44:3
3 For I will pour water upon him that is thirsty, and floods upon the dry ground: I will pour my spirit upon thy seed, and my blessing upon thine offspring: