Matthew Poole and continuators on John 7:38

38 He that believeth on me, as the scripture hath said , out of his belly shall flow rivers of living water .

We have had frequent occasion to open the term of believing on Christ: It may be doubted, whether those words (as the Scripture hath said) be to be referred to the first or latter part of the Text. If to the former, they are words expressive of that Faith to which the following Promise is made, which is not any assent, or slightly credit given to the word; but such a Faith as the Scripture hath spoken of; as that Faith which is justifying and saving.

The general sense of the Promises, That his Soul shall abound with all saving and comfortable Influences of saving Grace. The Belly signifieth the Heart (that part of man, which is called the Heart, being in the Belly.) So Iob 15.35. Psal. 40.8. the flowing of Rivers of water, signifieth the plenty of Spiritual Influences with which Believers shall be supplied; whether Joy, Knowledge, Spiritual Gifts, or Graces. If any ask, where the Scripture speaketh this? I Answer, in all those Promises we meet with in the Old Testament, about pouring out the Spirit.

Marginal references: Deut. 18.15.; Isa. 44.3.