A last will and testament is a legal document detailing how a person's assets and properties will be distributed after death. The will must identify the "testator" and the beneficiaries, their qualifications, and a description of what is being bequested to each of them.
The shedding of Christ's blood did three things: it paid God for the sinner's debt, purged the guilt from the sinner's conscience, and enabled the redeemed heirs to possess their inheritance.