This verse (chaupai) is from the Balakanda chapter of Shri Ramcharitmanas.
मुद मंगलमय संत समाजू। जो जग जंगम तीरथराजू॥ राम भक्ति जहँ सुरसरि धारा। सरसइ ब्रह्म बिचार प्रचारा॥
This verse (chaupai) is found in Balakanda, describing the company of saints as a form of pilgrimage.
Meaning : The company of saints is filled with joy and brings well-being; it is like a moving, living Prayagraj (the king of holy places) in the world. In this saintly gathering, there is the stream of devotion to Lord Ram, like the sacred Ganges, and the spread of knowledge of the divine, like the Saraswati river.