Hastings' Dictionary of the Bible (1898)
EAR'NEST. This is something going before or given in advance as a pledge of more in reserve; thus, earnest, or earnest-money, is a sum paid in advance as a pledge of full payment at a future time. In a spiritual sense, it denotes those gifts and graces which the Christian receives as a pledge or earnest of perfect holiness and happiness in the future world. 2 Cor 1:22; Eph 1:14.