"I, AB, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God."
Both the Senate and the House have the same oath.
Update:
(There are even links to who signed it)
http://www.atr.org/taxpayer-protection-pledgeIn the Taxpayer Protection Pledge, candidates and incumbents solemnly bind themselves to oppose any and all tax increases. While ATR has the role of promoting and monitoring the Pledge, the Taxpayer Protection Pledge is actually made to a candidate's constituents, who are entitled to know where candidates stand before sending them to the capitol. Since the Pledge is a prerequisite for many voters, it is considered binding as long as an individual holds the office for which he or she signed the Pledge.
Since its rollout with the endorsement of President Reagan in 1986, the pledge has become de rigeur for Republicans seeking office,
and is a necessity for Democrats running in Republican districts.
Today the Taxpayer Protection Pledge is offered to every candidate for state office and to all incumbents. More than 1,100 state officeholders, from state representative to governor, have signed the Pledge. Statehouse tax-and-spend interests have to contend with Pledge signers in every state.