Church leaders in Ireland have welcomed the new Prime Minister Micheal Martin.
Church of Ireland leaders said they want to assure Mr Martin that they are praying for him.
In a join statement, Most Rev John McDowell, Archbishop of Armagh and Primate of All Ireland, and Most Rev Dr Michael Jackson, Archbishop of Dublin and Primate of Ireland said:
'We will be writing to congratulate the new Taoiseach, Micheál Martin, and his government, on taking office, and want to assure them publicly of our prayers and good wishes, and those of the Church of Ireland community, as they take up office at a time of unique concern and uncertainty.
'This government will face unprecedented new challenges and wrestle with a number of unresolved old ones, as they try to reshape public policy for the benefit of all the citizens of Ireland. It is a task which will require prodigious energy, resourcefulness and trust. We wish the Taoiseach and his colleagues well in the days and years ahead."
The incoming prime minster hailed his new role as "one of the greatest honours which anyone can receive".
The Fianna Fail leader was elected Taoiseach of the 33rd Irish parliament, with 93 TDs voting in favour and 63 against. Three TDs abstained.
Mr Martin used his inaugural speech to pay tribute to the health workers and those who have died in the Covid-19 pandemic.
He told the Dail, sitting in Dublin's Convention Centre: "We are meeting away from our permanent chamber because of a historic pandemic which has struck Ireland and the rest of the world.
"As of today, 2,278 people on this island have lost their lives.
"Many thousands more have fought a long struggle to recover. There is no community, no part of our country, which has escaped untouched.
"In the last three-and-a-half months, enormous progress has been made in controlling the spread of the virus and treating those who have become sick.
"The struggle against the virus is not over. We must continue to contain its spread. We must be ready to tackle any new wave, and we must move forward rapidly to secure a recovery to benefit all of our people."
As he hailed the honour of being elected Taoiseach, Mr Martin paid tribute to his wife and children, and said he is proud of his working class roots.
He said: "Most of all I want to thank my family and my community. Without them I could have achieved nothing."
Mr Martin has taken over from Mr Varadkar in a historic reconciliation of a political feud with Fine Gael dating back to the foundation of the state a century ago.
Under the terms of a coalition deal, he'll hold the job until 2022, when it will rotate back to his predecessor.