Through Christ's own words we know him to be equal with God.
NO ONE who accepts the Scriptures as divine is entitled to deny that in His personal ministry the Lord Jesus laid claim to Deity. And the crucifixion is a public proof that He did in fact assert this claim. For we are told expressly that the reason why the Jews plotted His death was "because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God." (Joh 5:18) His claim to be "Lord even of the Sabbath" was in itself an assertion of equality with the God of Sinai...
And this He made unequivocally clear. The charge brought against Him was one from which, if false, any godly Israelite would have recoiled with horror. But instead of repelling it He accepted it in a way which even common men could understand. For He immediately asserted such absolute unity with God that the Father was responsible for His every act, including, of course, the miracle which they had denounced as a violation of the divine law. He next claimed absolute equality with God as "the author and giver of life" -- the supreme prerogative of Deity. And, lastly, He asserted His exclusive right to the equally divine prerogative of judgment.
"For the Father judgeth no man, but hath committed all judgment unto the Son: That all men should honour the Son, even as they honour the Father. He that honoureth not the Son honoureth not the Father which hath sent him. Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life. Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God: and they that hear shall live. For as the Father hath life in himself; so hath he given to the Son to have life in himself; And hath given him authority to execute judgment also, because he is the Son of man. Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation." -John 5:22-29