Final answer:
Protestant evangelism from Great Britain and Europe, part of the First Great Awakening, was the development most directly contributing to the events described by Benjamin Franklin, as it ushered in an era of emotional religious revival and widespread conversions across the colonies.
Step-by-step explanation:
The development that most directly contributed to the events described in the excerpt about the reception of the Reverend Mr. Whitefield in 1739 is Protestant evangelism coming to the colonies from Great Britain and Europe. This period, known as the First Great Awakening, was characterized by a surge of religious fervor and evangelical Protestant revivals. These revivals rejected the formal modes of worship and instead emphasized a personal and experiential faith. Figures like George Whitefield and Jonathan Edwards were central to this movement, fostering a spirit that led to the construction of new meeting houses to accommodate the large crowds that their preaching drew.
The Great Awakening promoted a fervent, emotional religiosity that was welcomed by many, including those who had felt excluded by traditional Protestantism. This led to increased church attendance, numerous conversions, and the spread of new evangelical Protestant denominations.