In 1778 he was ordained to the ministry in Concord, Massachusetts, where he continued for 63 years, preaching his last sermon the day after his 90th birthday.

At the time Ripley settled in Concord the town was divided into two religious factions, but he quickly succeeded in binding them in a union that existed for nearly 50 years.

In him perished more personal and local anecdote of Concord and its vicinity than is possessed by any survivor, and in his constitutional leaning to their religion he was one of the rear-guard of the great camp and army of the Puritans.

[1] In 1836, he gave land for the use of installing a monument to commemorate the battle of Concord, which had been fought on April 19, 1775.

Ripley was not present at either battle, and the consensus among historians (for example the late John Galvin, U.S. Army general and former Supreme Allied Commander of NATO forces) concluded that there is neither conclusive evidence nor agreement about which side fired first in either battle.