The Fifth Sunday after Trinity — Sixth Sunday after Pentecost — is July 4, 2021.
Readings for Year B can be found here.
The Gospel reading is as follows (emphases mine):
Mark 6:1-13
6:1 He left that place and came to his hometown, and his disciples followed him.
6:2 On the sabbath he began to teach in the synagogue, and many who heard him were astounded. They said, “Where did this man get all this? What is this wisdom that has been given to him? What deeds of power are being done by his hands!