Charles H. Spurgeon on Psalms 84:6

Who passing through the valley of Baca make it a well. Traversing joyfully the road to the great assembly, the happy pilgrims found refreshment even in the dreariest part of the road. As around a well men meet and converse cheerfully, being refreshed after their journey, so even in the vale of tears, or any other dreary glen, the pilgrims to the skies find sweet solace in brotherly communion and in anticipation of the general assembly above, with its joys unspeakable. Probably there is here a local allusion, which will never now be deciphered, but the general meaning is clear enough. There are joys of pilgrimage which make men forget the discomforts of the road. "The rain also filleth the pools." God gives to his people the supplies they need while traversing the roads which he points out for them. Where there were no natural supplies from below, the pilgrims found an abundant compensation in waters from above, and so also shall all the sacremental host of God's elect. Ways, which otherwise would have been deserted from want of accommodation, were made into highways abundantly furnished for the travellers' wants, because the great annual pilgrimages led in that direction; even so, Christian converse and the joy of united worship makes many duties easy and delightful which else had been difficult and painful.