Passage
He was not that light, but was sent to beare witnesse of that light.
He was not that light, but was sent to beare witnesse of that light.
John 1:6 There was a man sent from God, whose name was Iohn.
John 1:7 This same came for a witnesse, to beare witnesse of that light, that all men through him might beleeue.
John 1:8 He was not that light, but was sent to beare witnesse of that light.
John 1:9 This was that true light, which lighteth euery man that commeth into the world.
John 1:10 He was in the world, and the worlde was made by him: and the worlde knewe him not.
The verse centers on "light", "sent", "beare", and "witnesse". It is saying that the verse draws attention to "light" and "sent", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 7's "This same came for a witnesse to..." into verse 9's "This was that true light which lighteth...", so "light" and "sent" belong inside that flow. In John context, the local focus is the identity of Jesus, new birth, eternal life, and belief and unbelief.
A plain takeaway is to answer the verse's own emphasis on "light" and "sent" with trust shaped by these words, not by a vague optimism outside the passage.