72 Pa. Stat. § 5020-302
The elected and appointed assessors of the several wards, townships, towns, boroughs and districts, and, in townships of the first class, also the assistant township assessors and assistant triennial assessors, shall, immediately on the receipt of the precept from the county commissioners, or board of revision of taxes, or board for the assessment and revision of taxes, and before entering upon the duties of their office, take and subscribe the following oath or affirmation:
You do (swear or affirm) that you will support the Constitution of the United States and the Constitution of Pennsylvania, that you will, as assessor for (ward, district, borough, town or township), use your utmost diligence and ability to discover and ascertain all the property, real and personal, within your (ward, district, borough, town or township), and all other objects subject to taxation by the laws of this Commonwealth, and take an accurate account of the same; and that you will justly and honestly, to the best of your judgment, assess and value every separate lot, piece or tract of land, with the improvements thereon, and all personal property made taxable by the laws of this Commonwealth, within your (ward, district, borough, town or township), at the rate or price which you shall, after due examination and consideration, believe the same would sell for if sold singly and separately at a bona fide sale, after full public notice; and that you will assess all persons according to their correct offices and posts of profit, trades and occupations; and that you will perform your duty as assessor of said (ward, district or township) with honesty and fidelity, according to the laws of this Commonwealth, without fear, favor or affection, hatred, malice or ill will.
72 P.S. § 5020-302