"I cannot imagine that I am here so far and my friend has gone," he said recalling his decades-old friendship with Jaitley.
Towards the end of his address to the Indian community here, Modi told the gathering that he was in deeply pained over the demise of Jaitley earlier in the day.
Modi said these were difficult moments for him as he was bound by duty on one side and on the other side there were abiding memories of friendship.
The Prime Minister said that Bahrain was filled with enthusiasm and India was celebrating the festival of Janmashtami but for him, there was a feeling of pain.
"At this moment, I am standing before you with deep pain in my heart. From student life, the friend with whom step after step of public life was taken, the political journey was undertaken... staying connected with each other at every moment, facing struggles together, dreaming together and working for realisation of dreams, such a long journey was done with that friend Arun Jaitley, India's former Defence Minister, Finance Minister, he passed away today. I cannot imagine that I am here so far and my friend has gone," Jaitley said.
He also remembered party leader and former union minister Sushma Swaraj who died on August 6.
"Some days back, our former external affairs minister sister Sushmaji passed away. Today my friend Arun has gone. I am facing difficult moments. One one side I am bound by duty and on the other, there are feelings of friendship. From Bahrain, I pay my tributes, bow to him, I pray that Almighty gives courage to his family members," Modi said.
( With inputs from ANI )