Plural Term - Explanation 

Jesus Christ is not the Image of word alone, but the Image of invisible trinity God, that means in Jesus Christ we can see our Heavenly Father (I and the Father are one - John 10:30), and the Son (He who came down from heaven, that is, the Son of Man who is in heaven - John 3:13), and the Holy Spirit (if I do not go away, the Helper will not come to you - John 16:7).

When Jesus Christ spoke about himself he spoke in plural manner, because he is an image of of Trinity (Father, Word, and the Holy Spirit).

We speak that we do know - Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness - John 3:11

We worship what we know - You worship what you do not know; we worship what we know, for salvation is from the Jews - John 4:22 

Who has believed what he heard from us - While you have the light, believe in the light, that you may become sons of light. When Jesus had said these things, he departed and hid himself from them. Though he had done so many signs before them, they still did not believe in him, so that the word spoken by the prophet Isaiah might be fulfilled: Lord, who has believed what he heard from us, and to whom has the arm of the Lord been revealed? - John 12:36-38

We will come to him - Jesus answered him, If anyone loves me, he will keep my word, and my Father will love him, and we will come to him and make our home with him - John 14:23