The NT writers often quoted the OT passage of YHWH; pointing to Isaiah often, who taught that there is only one YHWH and there are no other gods besides YHWH, none else, none exist.
Those same NT writers that quote Isaiah's teaching of one YHWH, also repeatedly quote Isaiah verses of YHWH, and tell us YHWH is Jesus Christ.
It is the OT writers, who tell us of the unique divine, uncreated, eternal, omniportent, omniscient nature of YHWH.
It is the NT writers, who tell us Jesus is YHWH.