On John 7:37 [“On the last day of the feast, the great day, Jesus stood up and cried out, ‘If anyone thirsts, let him come to me and drink’”], Bonar writes:
“Who are they who need this living water? Not heathens; not profane and irreligious; but Jews; religious Jews; engaged in the worship of God, at one of their most joyful feasts. This is remarkable.
In the fourth chapter it is to the Samaritan that he presents the cup of living water. In the book of the Revelation, it is offered indiscriminately to all, Jew and Gentile. So also in the fifty-fifth of Isaiah. But here it is to the Jew, the religious Jew. He is the thirsty one, he needs living water.
His rites, and feasts, and sacrifices cannot fill him, nor quench his thirst. He has still a deep void within,—an intense thirst, which calls for something more spiritual and divine. It is not then to the idolatrous pagan that the Lord speaks; not merely to the lover of pleasure or lust; the heedless sinner. It is to the men who frequent the sanctuary,—who pray and praise outwardly; who go to the Lord’s table. It is to them He speaks. Perhaps the thirstiest of our race are to be found among our so-called religious men,—and I do not mean the hypocrite or Pharisee,—but those who, with devout conscientiousness, attend to what are called religious duties in all their parts.
They go through the whole round and routine of service, but they are not happy. They are still thirsty and weary. This external religiousness helps to pacify conscience, but it does not make them happy. Sabbath comes after Sabbath, and finds them in their place in the sanctuary, but they are not happy. It is a form or a performance; an empty vessel. They are just where they were. There are multitudes of such in our day; in our churches; at our communion tables, To them Jesus speaks, ‘If any man thirst, let him come to me and drink.’ Duties, ceremonies, and performances cannot make you happy. They are a weariness. They leave you often more thirsty than before. But deal with Jesus, as God’s gift, as the dispenser of God’s gift,—you will find in Him the fountain of living water.”
—Horatius Bonar, Light and Truth: Bible Thoughts and Themes (Dust & Ashes, 2002), 2:250—251.