1 Timothy 6:10

For the love of money is the root of all evil
Of all the evils before mentioned, and of others; not money itself, as silver and gold, which are God's creatures, and his gifts, and may be used to, and answer many good purposes; but the love of it, and not any love of it; for there may be a lawful love of it, and desire after it, so far as it is requisite to the necessaries of life, to answer the calls of Providence, the duties we owe to God and men, to serve the interest of Christ, and do good to fellow creatures and fellow Christians: but it is an immoderate insatiable desire after it, and an inordinate love of it, which is here meant, such as is properly idolatry: as when a man loves it, not only besides, but above God; serves it as if it was God, and places his trust and confidence in it, independent of God, and his providence; such love of it is the source and spring of all iniquity, as above; it was the sin of Judas, and the root of all his iniquity. The phrase is Jewish. So idolatry is said to be (twnwe lk rqye) , "the root of all iniquities" ^F17; see ( Hebrews 12:15 )

which while some coveted after;
in a greedy and insatiable way:

they have erred from the faith;
the doctrine of faith. Observing that the professors of it are generally poor, they have declined that path, and have not so much as heard the word; and if they have heard and embraced it, yet when persecution arises because of it, they drop their profession of it; or else their minds are so filled with worldly cares, and deceitful riches, that the word is choked, and becomes unprofitable, and by and by, Demas like, they forsake it, having loved this present world.

And pierced themselves through with many sorrows;
riches are therefore fitly compared to thorns, which give great trouble and uneasiness, both in getting and keeping them; and oftentimes the reflection upon the unlawful ways and means made use of to obtain them, gives very pungent pain and distress; see ( Job 20:15-29 ) . The apostle seem to allude to the Hebrew word (eub) , used for a covetous man, which signifies one that pierces, cuts, and wounds, as such an one does both himself and others.