Assurance by C H Spurgeon and published by Classics.
Spurgeon writes ""They say they are saved, and they stick to it; they simply are, and they think it wicked to doubt it; but yet they have no reason to warrant their confidence. There is a great difference between presumption and full assurance.
Full assurance is reasonable: it is based on solid ground.
Presumption takes for granted, and with brazen face pronounces that to be its own to which it has no right whatever." This book seeks to show the difference between assurance and presumption by recording in detail, what full assurance is, the true position of assurance and help to obtain full assurance.