Worshippers at All Hallows by the Tower thanked God for all of the runners taking part regardless of their ability and for the money and attention they'll be raising for good causes.
The Christ Faith Tabernacle Youth Choir also sung at last night's service, which was broadcasted live on the social media app Periscope and can be watched again.
All Hallows by the Tower, which is situated on Mile 23 of the London Marathon, will be open on race day for the public to come in and light a candle, pray, have a chat and rest.
In all 40,000 runners are taking part, including celebrities such as former Welsh rugby international Shane Williams, Olympic gold medallist Dame Kelly Holmes, radio presenter Chris Evans and the actress Natalie Dormer.
Revd Bertrand Olivier, the vicar at All Hallows by the Tower is running today's marathon himself and told Premier: "I was inspired to start running by watching all these people.
"It's not just very well-honed athletes but people in all circumstances, of all body shapes, remembering loved ones who have died and then raising funds.
"It is wonderful to be able to use our God-given gifts and talents - particularly our bodies in this case - in order to benefit others.
"All those of us who can do something for others, do it, and therefore benefit the greater good."
Listen to Premier's Aaron James speaking to Revd Bertrand Olivier:
