"It is told that the tzaddik Rabbi Uri of Starlisk (the Seraph) once said that if only his father would have immersed in a mikveh (ritual bath) once in his lifetime, Rabbi Uri's service of God would have been immeasurably easier.
No person—even the greatest tzaddik—can ever completely disassociate himself from the garments he inherited, and any deficiencies they contain will be a perpetual challenge to him.
Conversely, a person who merited to inherit a hallowed garment is thus empowered to achieve great heights in holiness, even if his own soul is of a lesser spiritual quality.
This concept is the basis for the importance traditionally accorded to yichus, 'ancestry and lineage.'
A soul is not inherited, but its garments are.
These garments impart certain qualities to the soul, such as nobility, refinement, and talent.
This garment is passed on from parent to child even if the child is of an entirely different caliber.
A lofty garment can be bestowed upon the lowliest of the lowly, in which case, even if he chooses to descend to the depths of depravity, his holy garment will interfere with his lifestyle.
It is not that people of an exalted lineage sin less; it is that they cannot enjoy their sins as much as a sinner of lesser parentage.
Their lofty garments get in the way; their holy ancestry burdens them and robs them of their capacity to transgress with abandon.
There is no guarantee that a person of holy ancestry will be a great person, but somehow, something always remains.
If we study this phenomenon closely, we see that this is not only a matter of education but also of the personality that one is born with, a sort of brand burned into his soul.
Our generation abounds with such individuals—people whose soul's garment gives them no rest and does not allow them to sin easily or with pleasure, who are driven by mysterious internal forces, often against their conscious will.
Try as they may, they cannot shed the garment that garbs their soul by virtue of their lineage."
–Rabbi Adin Steinsaltz
From Opening the Tanya by Rabbi Adin Steinsaltz