How do we know that John the Baptist was chosen by God?

John the Baptist stands as a pivotal figure in salvation history, known for his clear calling as the forerunner of Christ. His choice by God is not arbitrary; rather, it illustrates the concept of sovereign grace in which God acts according to His divine will. In Luke 1:15, it is recorded that John was filled with the Holy Spirit even in his mother’s womb, marking him out as selected for a special purpose. His life exemplifies the grace given to some, while others, like Herod, are justly left to pursue their sinful inclinations. This distinction underscores God's sovereign mercy, as articulated in Romans 9:15, where He states, 'I will have mercy on whom I have mercy.'