It was the principal end of Christ’s institution of the Sacrament of the Supper, that he might assure them of his love, and that he might seal up to them the forgiveness of their sins, the acceptance of their persons, and the salvation of their souls (Matt. 26:27-28). The nature of a seal is to make things sure and firm among men; so the Supper of the Lord is Christ’s broad seal, it is Christ’s privy-seal, whereby he seals and assures his people that they are happy here, that they shall be more happy hereafter, that they are everlastingly beloved of God, that his heart is set upon them, that their names are written in the book of life, that there is laid up for them a crown of righteousness, and that nothing shall be able to separate them from himwho is their light, their crown, their all in all (2 Tim. 4:8; Col. 3:11). In this sacrament Christ comes forth and shows his love, his heart, his bowels, his blood, that his children may no longer say, ‘Doth the Lord Jesus love us? Doth he delight in us, &c?’ but that they may say with the spouse, I am my beloved’s and his desire is towards me(Songs 7:10).
Many precious Christians there are, that have lain long under fears and doubts, sighing and mourning, and that have run from minister to minister, and from one duty to another, &c, and yet could never be persuaded of the love of Christ to their poor souls, but still their fears and doubts have followed them, till they have waited upon the Lord in this glorious ordinance, by which the Lord hath assured them of the remission of their sins, and the salvation of their souls. In this ordinance God hath given them mannahto eat, and a white stone, and new name, which no man knoweth, but he that receiveth it. Tell me, you precious believing souls, whether you have not found God in this ordinance, often whispering of you in the ear, saying, Sons and daughters be of good cheer, your sins are forgiven you? I know you have.
– Thomas Brooks (1608–1680), Heaven on Earth (1654), p.23-25.