Everyone that thirsteth come ye to the waters, and he that hath no silver; come ye, buy and eat; yea, come, buy wine and milk without silver and without price (Isa. 55:1); and also in Jeremiah (Jer. 13:1-2, 11). In Matthew:

The kingdom of the heavens is like unto treasure hid in the field; which when a man hath found, he hideth, and in his joy he goeth and selleth all that he hath, and buyeth that field. Again, the kingdom of the heavens is like unto a merchantman, seeking goodly pearls, and he went and sold all that he had, and bought it (Matt. 13:44-46). Again:

The prudent virgins said to the foolish ones, Go ye to them that sell, and buy for yourselves. And while they went to buy, the bridegroom came (Matt. 25:9-10). [2] As "buying" signifies appropriation, therefore in the Word the things bought with silver are well distinguished from those otherwise obtained. Moreover, the servants bought with silver were as one's own, and in a lower degree like those born in the house; and therefore they are often mentioned together, as in Genesis:

Circumcising he shall be circumcised that is born in thy house, and he that is bought with thy silver (Gen. 17:13);

and in Leviticus:

If a priest buy any soul with the purchase of silver, he and one that is born in his house, they shall eat of his bread (Lev. 22:11). Hence it is evident what is signified by the "redeemed (or those bought back) of Jehovah," in the Word, namely, those who have received good and truth, and thus those to whom the things of the Lord have been appropriated.