What Is Surety in the Bible? 
In OT references, the word “surety” refers to a person who intervenes on behalf of another. This person is a guarantor who takes the debt of an insolvent debtor, sometimes by substituting himself for the debtor. The act of intervening was often symbolized by shaking hands.
Cosigning
Cosigning is a form of debt-commitment in which one party pledges goods or money as a guarantee for a higher obligation. It is a form of borrowing from another person in exchange for the right to pay the loan later. Although not a biblical law, surety is one of God’s financial principles that can help keep us on the right path and out of money traps.
Biblical verses warn against cosigning loans and taking on the debts of strangers. In the Book of Solomon, chapter 6, the author explains the dangers of taking on loans. A cosigner may have to forfeit all of his possessions if he is unable to pay back the debt.
Verbal surety
Suretyship in Jewish law is recognized in many ways. It can exist before or after the creation of the principal obligation. Some scholars hold that a surety is liable for the entire debt; others hold that a surety does not owe anything. A surety can be a person whose only claim is that he passes on a debt to the debtor.
It has been argued that suretyship can be established verbally after establishing the principal obligation. This form of suretyship was used in biblical times, fell into disuse during the Talmudic period, and then re-emerges in post-talmudic times under the influence of other legal systems. However, there is a difference between a verbal suretyship and a written suretyship.
Unsolicited surety
Scripture warns Christians against uninvited surety. Suretyship, a relationship where one party pledges their future in exchange for a payment, violates the biblical principle of abstinence. This principle is violated by over 95 percent of Christians.
Biblical texts do not explicitly prohibit suretyship, but they generally do not encourage it. Biblical sureties must agree to fulfill their obligations, and they must follow the rules of the covenant. A covenant between surety and creditor is an act of faith, a commitment to a certain set of conditions.
While surety is not biblical law, it is an important principle of God’s law regarding money. If you fail to pay, you’ll risk breaching God’s covenant with you. Surety is one of the simplest cautions in God’s Word, but few pastors teach it. Broken promises cause broken relationships and financial hardship. In marriage, for example, failure to pay can cause tension and suspicion between spouses.
Losing your shirt
The concept of being a surety is not a positive one. In the Bible, suretyship is considered to be a bad thing. When you pledge security for someone else’s debt, you risk losing your shirt. Even if you have the best of intentions, it is not a good idea to give your shirt as collateral for a debt.
Jesus as a surety
The Bible presents Jesus as a surety, an individual who assumes responsibility for the debt of a debtor. As the Son of God incarnate, Christ bore the sins of the world. His death brought under the justice of God the penalty that was due to sin. As a result, Jesus was purposed as both a Surety and Substitute. This purpose was not lost on the Old Testament saints.
The term “surety” occurs only one other time in the New Testament. It’s a legal term referring to a person who takes responsibility for fulfilling an obligation. In the Bible, Jesus is the surety of a covenant; he promises to meet all of the covenant’s provisions forever.