Cleaving to the tzaddik spreads his wellsprings
Avraham · wells · tzaddik · wellspring · influence
מ"ש אשר חפרו עבדי אביו הוא כמ"ש כרוה נדיבי עם כו'.
That which is written, "which the servants of his father had dug" (Bereishis 26:15), is as it is written: "the nobles of the people dug it (karuha nedivei am)" (Bamidbar 21:18), etc.
The Sefas Emes links the wells dug by Avraham's servants in Toldos with the well of the Song at the Well, "dug by the nobles of the people."
הם עבדי אברהם כמ"ש נדיבי עמים נאספו כו'.
They are the servants of Avraham, as it is written: "the nobles of the peoples were gathered, the people of the God of Avraham" (Tehillim 47:10), etc.
The "nobles" are identified with Avraham Avinu's followers — those drawn after him are called the "nobles of the peoples, the people of the God of Avraham."
וע"י אברהם שהי' מעיין נובע יכלו אנשיו לחפור בארות להמשיך ממקור המעיין לכל הבארות.
And through Avraham, who was a flowing wellspring (ma'ayan nove'a), his people were able to dig wells, to draw from the source of the spring into all the wells.
Avraham himself was an ever-flowing spring of holiness; because of that source, his followers could "dig wells" — open channels that drew his living waters out to others.
וז"ש במחוקק במשענותם כי המתחדרין אל הצדיק יכולין להפיץ מעינותיו חוצה כנ"ל:
And this is what is meant by "with the lawgiver (mechokek), with their staffs (mishanosam)" (Bamidbar 21:18) — for those who attach themselves to the tzaddik are able to spread his wellsprings outward, as above.
"With the lawgiver, with their staffs" hints that those who draw close to the tzaddik gain the power to "spread his wellsprings abroad" — to carry his inner light and Torah out into the wider world.
Summary: The wells dug by Avraham's servants are the same as the well "dug by the nobles of the people." Because Avraham Avinu was an ever-flowing wellspring of holiness, those who attached themselves to him could open channels to draw from his source. So too, those who cleave to a tzaddik gain the ability to spread his wellsprings outward — carrying his light and Torah to others.