The apostle referred to ten Old Testament scriptures from Hebrews 1:5 to the end of the chapter. This text comes from Psalm 45:6-7. Both biblical Christology -the doctrine of Christ- and Soteriology -the doctrine of salvation are addressed. The heavenly Father addressed the Son as "God", sovereign and eternal. The authority of His kingdom is "righteousness", His essential and earned righteousness. By the latter, God justified.