William Burkitt on John 7:37

The feast of tabernacles (which is the first here meant) lasted eight days; the first and last of which were to be kept holy with religious assemblies and sacrifices; and it was a custom among the Jews, upon that solemn day, to offer up a pot of water unto God, which they drew out of the fountain of Siloam: with reference to this custom, Christ here cries with a loud voice, inviting the people to fetch and draw from him, as from a living fountain, all the sanctifying gifts and saving graces of the Holy Spirit.

Learn hence, That Jesus Christ is the original and fountain of all saving grace, whom, if we thirst after, repair to, and by faith depend upon, as a Mediator, we shall certainly receive what influences of grace soever we want and stand in need of.