There is only ONE god, and this is Yahweh (If Jesus is a separate, junior god, not falling under the "Yahweh" title, then where does this leave him?)
Deut 4: 35 (YLT): Thou, thou hast been shewn [it], to know that Jehovah He [is] God; there is none else besides Him.
Deut 4:35: (YLT): that Jehovah He [is] God, in the heavens above, and on the earth beneath -- there is none else.
ISAIAH 43:10,11 — 10 Ye [are] My witnesses, an affirmation of Jehovah, And My servant whom I have chosen, So that ye know and give credence to Me, And understand that I [am] He, Before Me there was no God formed, And after Me there is none. 11 I -- I [am] Jehovah, And besides Me there is no saviour. (YLT)
ISAIAH 44:24 (YLT): Thus said Jehovah, thy redeemer, And thy framer from the womb: `I [am] Jehovah, doing all things, Stretching out the heavens by Myself, Spreading out the earth -- who [is] with Me? 6
ISAIAH 44:6: (YLT) Thus said Jehovah, king of Israel, And his Redeemer, Jehovah of Hosts: `I [am] the first, and I the last, And besides Me there is no God.
In the NT, Jesus is often contextually equated with YHWH.
As explained in http://www.tetragrammaton.org, "In Romans 14:3-9, the early and late context talks about Christ. However, in the main body of the verses, within the context of teaching about Christ, Paul used Kyrios and God as functional synonyms. In these passages, Kyrios was often given attributes belonging only to God."