“Have I truly believed in Christ?” “Am I justified before God?” “How can I have assurance that I am a forgiven child of God?”
Questions like these can be dreadfully vexing to any person who takes the claims of the Gospel seriously. Assurance of Grace and Salvation are of such magnitude that our Confession dedicates an entire chapter to help believers in their questions concerning their condition before God.
There we are taught, “in the right use of means” a Christian “may in this life be certainly assured that they are in the state of grace.” One of the means that The Lord Jesus Christ has given to His people, so that they may enjoy confidence in their safety in Him is the Lord’s Supper.
Puritan Thomas Brooks offers these helpful words on assurance and the Supper:
“It was the principal end of Christ’s institution of the sacrament of the supper that he might assure his people of his love, and that he might seal up to them the forgiveness of their sins, the acceptation of their persons, and the salvation of their souls, Mat. xxvi. 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 [personal] 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 him who is their light, their life, their crown, their all in all.
In this sacrament Christ comes forth and shews his love, his heart, his bowels [compassion], his blood, that his children may no longer say; ‘Doth the Lord Jesus love us? doth he delight in us?’; but that they may say with the spouse, ‘ I am my beloved’s, and his desire is towards me,’ Cant. vii. 10. Many precious Christians there are that have lain long under fears and doubts, sighing and mourning; that have run from minister to minister, and from one duty to another, etc., 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 manna to eat, and a white stone, and new name, which no man knoweth but he that receiveth it. Rev. ii. 17. Tell me, ye 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’? Mat. ix. 2. I know you have!”
So, Christian taste the Bread and drink from the Cup and know that you are forgiven!David Charles, Pastor Providence Reformed Baptist Church Toledo, OH
 See chapter eighteen of the Second London Baptist confession of faith of 1677/89
 Works of Thomas Brooks vol. 2 pg 326