In legal terms, a guarantor is someone who takes responsibility for another. For example, if you an entering into a contract with someone (say you need to rent a house) but you are not "qualified", the renter may ask for a guarantor to support your application. The strength of the contract is therefore premised upon the integrity and worth of the guarantor.  

When God enacted the new covenant - a form of a contract for the believer, it was Jesus that became the guarantor of that contract and what this means is that God is bound to make good on the terms of the contract based on the merit of Jesus Christ. God as a covenant-keeping God moves in your life not necessarily because you know how to pray, or sing or even good deeds you have done but primarily because of the Guarantor of the New Covenant - the Lord Jesus. 

 #mediator #confidence #guarantee #surety