INSTANT.Instant and instantly are now used only of time. In AV [Note: Authorized Version.] they have their earlier meaning of urgent, urgently, as in Luk_23:23 they were instant with loud voices, requiring that he might be crucified; Luk_7:4 they besought him instantly (RV [Note: Revised Version.] earnestly). Cf. Erasmus, Paraphrase, i. 31, whoso knocketh at the doore instantly, to him it shal be opened.
Hastings' Dictionary of the Bible
Edited by James Hastings, D.D. Published in 1909
Instant. In the Authorized Version, means urgent, urgently or fervently, as will be seen from the following passages: Luk_7:4; Luk_23:23; Act_26:7; Rom_12:12.
Smith's Bible Dictionary
By Dr. William Smith.Published in 1863