Smith's Bible Dictionary

Earnest (2 Corinthians 1:22; 2 Corinthians 5:5; Ephesians 1:14) The Hebrew word was used generally for pledge, (Genesis 38:17) and in its cognate forms for surety, (Proverbs 17:18) and hostage. (2 Kings 14:14) The Greek derivative, however, acquired a more technical sense as signifying the deposit paid by the purchaser on entering into an agreement for the purchase of anything. In the New Testament the word is used to signify the pledge or earnest of the superior blessings of the future life.