Passage
No one has seen God at any time; the only-begotten Son, who is in the bosom of the Father, *he* hath declared [him].
John 1:18 (DBY)
Nearby Context
John 1:16 for of his fulness we all have received, and grace upon grace.
John 1:17 For the law was given by Moses: grace and truth subsists through Jesus Christ.
John 1:18 No one has seen God at any time; the only-begotten Son, who is in the bosom of the Father, *he* hath declared [him].
John 1:19 And this is the witness of John, when the Jews sent from Jerusalem priests and Levites that they might ask him, Thou, who art thou?
John 1:20 And he acknowledged and denied not, and acknowledged, I am not the Christ.
Study Lenses
The verse centers on "only begotten Son", "seen", "time", "bosom", "father", "hath", and "declared". It is saying that the verse draws attention to "only begotten Son" and "seen", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 17's "For the law was given by Moses..." into verse 19's "And this is the witness of John...", so "only begotten Son" and "seen" 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 "only begotten Son" and "seen" with trust shaped by these words, not by a vague optimism outside the passage.