The biblical basis for a confession of sin in the context of Communion is 1 Corinthians 11:1 7-34. St. Paul says that unworthy reception of the Blessed Sacrament can cause harm. Therefore he writes, “let a man examine himself and so let him eat of that bread or drink of that cup.” The requirement that we be in love and charity with our neighbors comes from St. Matthew 5:23-24, where Jesus mandates that we be reconciled with our brother before we offer our gift on the Altar. These requirements are set forth in the longer exhortation (BCP 84) and are stressed in the Offices of Instruction (BCP 292).
The familiar routine of general confession should not keep us from practicing specific confession. Specific confession means that we not only admit we have sinned in thought, word and deed; it means we also confess the specific thoughts, words and deeds. Part of our preparation for worship is self-examination, which should bring to mind the specific sins for which we will offer this prayer. It is highly profitable to augment general confession with the regular practice of making a specific confession to a priest.