fur'-vent (dalaq; ektenes, zeo): "Fervent" (from Latin fervere, "to boil") does not occur in the King James Version of the Old Testament, but the Revised Version (British and American) gives it as the translation of dalaq, "to burn" (Pr 26:23), instead of "burning," "fervent lips and a wicked heart." In the New Testament it is the translation of ektenes, "stretched out," hence, intent, earnest (1Pe 4:8, "being fervent in your love among yourselves"); of zeo, "to boil," "to be hot" (Ro 12:11, "fervent in spirit," Ac 18:25); of zelos, "zeal," "fervor" (2Co 7:7, the Revised Version (British and American) "zeal"), in Jas 5:16 the King James Version has: "The effectual fervent prayer of a righteous man availeth much," where the Greek is: polu ischuei deesis dikaiou energoumene, which the Revised Version (British and American) renders, "The supplication of a righteous man availeth much in its working."
⇒See the definition of fervent in the KJV Dictionary
"Fervently" is the translation of agonizomai, "to strive or struggle" (agonize), Col 4:12 the King James Version, the Revised Version (British and American) "Epaphras .... striving for you in his prayers"; of ektenos, literally, in an outstretched manner (1Pe 1:22, the Revised Version (British and American) "Love one another from the heart fervently"; compare 1Pe 4:8, "fervent in your love among yourselves"). Christian love too often lacks this fervency, but Christ's love for us was "stretched out" to the uttermost.
The Revised Version (British and American) has "fervently" for "earnestly" (Jas 5:17, margin "with prayer").
W. L. Walker