What does it mean that insistence on a minor sin makes it a major sin, and is this statement correct with evidence, and is shaving the beard—which is considered a minor sin—forgiven by persistent seeking of forgiveness, and how are minor sins expiated?

Persistence in minor sins makes them major sins. Thus, there is no minor sin with persistence, and no major sin with seeking forgiveness. Therefore, a Muslim must avoid belittling sins. Their example is like that of people who descended into a valley and gathered firewood little by little until they baked their bread with it. So, when a servant is taken to task for belittled sins, they destroy him. Minor sins are expiated by avoiding major sins, by good deeds, by calamities, by seeking forgiveness, and by sincere repentance.