The World Evangelical Alliance and the World Council of Churches both say there must be an immediate end to violent hostilities in Israel and the Palestinian territories.
On Sunday, Pope Francis renewed his appeal for dialogue and an end to the violence in Gaza.
"WEA calls for an immediate end to the violent hostilities in the Israeli-Gaza conflict and for both sides to return to good faith negotiations," the World Evangelical Alliance said in a statement Monday.
World Council of Churches general secretary Rev. Olav Fykse Tveit said in a statement Tuesday, "Hostilities must cease.
"Israel, Palestine and the surrounding region must be offered the hope of peace: a peace based in justice, a lasting peace that may lead toward reconciliation."
Tveit expressed deep sadness over the "human devastation on every side, and the disproportionately high number of Palestinian civilian casualties, including women and children."
Between them the Catholic Church, the World Council of Churches and the World Evangelical Alliance represent nearly all of the planet's 2 billion Christians.
The situation in the occupied Gaza Strip is critical for the civilians living there and requires the urgent attention of the U.N. Human Rights Council, Navi Pillay the United Nations human rights chief said Wednesday.
At a special session of the council the U.N. high commissioner said that since Israel announced its military operation "Protective Edge" on July 7, Gaza has been subjected to daily intensive bombardment from the air, land and sea, employing well over 2,100 air strikes alone.
The hostilities have resulted in the deaths of more than 600 Palestinians, including at least 147 children and 74 women.
"This is the third serious escalation of hostilities in my six years as High Commissioner. As we saw during the two previous crises in 2009 and 2012, it is innocent civilians in the Gaza Strip, including children, women, the elderly and persons with disabilities, who are suffering the most.
"According to preliminary UN figures, around 74 percent of those killed so far were civilians, and thousands more have been injured. Those numbers have climbed dramatically since Israel's ground operations began on 17 July."
"As we speak, the indiscriminate firing by Hamas and other armed groups of more than 2,900 rockets, as well as mortars, from Gaza continues to endanger the lives of civilians in Israel. I have repeatedly condemned such indiscriminate attacks in the past. I do so again today."
WEA quoted Dr. Geoff Tunnicliffe, its secretary general, who said in speech in Bethlehem earlier this year, "The suffering, grief and despair of Christians, Muslims or Jews are an affront to humanity. Their suffering, grief and despair are an affront to God."
Rev. Harry Tees, WEA Holy Land ambassador said, "We, the Evangelicals in the Middle East and in particular in the Holy Land, are saddened by the spiral of violence that once again is ripping through our beloved neighborhoods.
"We call the World Wide Church to join us for a time of prayer and fasting. We have much to repent of ourselves - the attitudes of blame and accusation."
Dr. Munir Kakish, chairman of the Council of Local Evangelical Churches in the Holy Land, representing evangelicals in the Palestinian Territories, said, "We ask Israelis and Palestinians to stop the fighting.
"We as a council want to be a bridge of peace to all people. We feel very strongly that killing - no matter where - is not a Godly response. War is not the answer. Negotiations are the proper path to solve conflicts."
The WCC's Tveit appealed to all parties to stand by their obligations under international humanitarian and human rights law which condemn and prohibit all kinds of indiscriminate and disproportionate killing of civilians.
Tveit noted the WCC's call for an immediate cessation of hostilities in Gaza. He urged lifting of restrictions on the movement of people and goods in and out of the Gaza Strip so that urgent humanitarian needs can be dealt with.
The WCC also called for the resumption of direct peace talks to achieve a comprehensive and sustainable peace based upon a two-state solution along internationally recognized borders.
Tveit said that the "latest resort to armed conflict - and the consequent intolerable suffering inflicted on families and communities - can do nothing to promote a just and sustainable peace for Israelis and Palestinians."