"27And ye also shall bear witness, because ye have been with me from the beginning." (John 15: 27)
"You have been with me from the beginning" may seem to refer to Jesus' ministry.
The original language of the text is even more compelling, since a literal translation would read "from beginning".
This same construction opens up the Gospel of John:
"In the beginning was the Word, and the Word was with God, and the Word was God." (John 1: 1)
"In beginning" would be the accurate translation, a statement which communicates the very beginning, the outset of time, of everything, the same words which open up the entire Word of God (Genesis 1: 1)
How is it possible for Jesus then to say "You have been with me from the beginning"?
First of all, God is outside of time:
"Behold, thou hast made my days as an handbreadth; and mine age is as nothing before thee: verily every man at his best state is altogether vanity. Selah." (Psalm 39: 5)
We are slight creatures, grants, in the eyes of the omnipotent Lord, yet the magnitude of this greatness must reflect on how great He is, not how little we are in comparison.
Also:
"For a thousand years in thy sight are but as yesterday when it is past, and as a watch in the night." (Psalm 90: 4)
Peter quoted this verse with a greater emphasis on the negligible effect of time to Him:
"But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day." (2 Peter 3: 8)
We are now one with Christ, seated in heavenly places in Him (Ephesians 2: 6). We are in the Kingdom of Heaven (Romans 14: 17), and in Christ we have eternal life (John 3: 16)
This wonderful gift touches our spirit, even though we currently live in a dying body. As far as God the Father is concerned, however:
"As He is, so are we in this world." (1 John 4: 17)
Jesus is the same yesterday, today, and forever (Hebrews 13: 8). We are partakers of His divine nature (2 Peter 1: 4), which means that when we receive Him, we in effect step into His timelessness, as well.
Because we are in Christ, and Christ is throughout all time, we can then claim that we have been with Him "from beginning."
Meditate on this powerful, wonderful truth, for this wonder will give us greater grace to receive:
"For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come, 39Nor height, nor depth, nor any other creature, shall be able to separate us from the love of God, which is in Christ Jesus our Lord." (Romans 8: 38-39)
and
"5Let your conversation be without covetousness; and be content with such things as ye have: for he hath said, I will never leave thee, nor forsake thee." (Hebrews 13: 5)