Easton's Bible Dictionary: M. G. Easton, M.A., D.D.

Call

1. To cry for help, hence to pray (Gen. 4:26). Thus men are said to "call upon the name of the Lord" (Acts 2:21, 7:59, 9:14; Rom. 10:12; 1 Cor. 1:2).
2. God calls with respect to men when he designates them to some special office (Ex. 31:2; Isa. 22:20; Acts 13:2), and when he invites them to accept his offered grace (Mt. 9:13, 11:28, 22:4).

   In the message of the gospel his call is addressed to all men, to Jews and Gentiles alike (Mt. 28:19; Mk. 16:15; Rom. 9:24, 25). But this universal call is not inseparably connected with salvation, although it leaves all to whom it comes inexcusable if they reject it (Jn. 3:14-19; Mt. 22:14).

   An effectual call is something more than the outward message of the Word of God to men. It is internal, and is the result of the enlightening and sanctifying influence of the Holy Spirit (Jn. 16:14; Acts 26:18; Jn. 6:44), effectually drawing men to Christ, and disposing and enabling them to receive the truth (Jn. 6:45; Acts 16:14; Eph. 1:17).