Great sins

“But again you say, suppose that a man’s sins be exceeding great, gross, and heinous; for I do confess that possibly a godly man may sin some sin against his light, and against his conscience sometimes; but as for me, my sin is exceeding great, gross and heinous, and have I not just cause and reason now to be discouraged?

No, not yet, for though your sin be great, is not God’s mercy great, exceeding great? Is not the satisfaction made by Christ great? Are the merits of Christ’s blood small? Is not God, the great God of heaven and earth, able to do great things? You grant that God is almighty in providing for you, and is He not almighty also in pardoning? Will you rob God of His almightiness in pardoning?
You say your sin is great, but is it infinite? Is not God alone infinite? Is your sin as big as God, as big as Christ? Is Jesus Christ only a Mediator for small sins?
Now look what David says in Psalm 25:11, “For thy names sake, O Lord, Pardon mine iniquity, for it is great.” If David use this reason, then may you also; and if this be a reason why God should pardon sin, because it is great, then this cannot be a reason, a just reason, why you should be discouraged.”