Passage
and he looked upon Jesus as he walked, and saith, Behold, the Lamb of God!
John 1:36 (ASV)
Nearby Context
John 1:34 And I have seen, and have borne witness that this is the Son of God.
John 1:35 Again on the morrow John was standing, and two of his disciples;
John 1:36 and he looked upon Jesus as he walked, and saith, Behold, the Lamb of God!
John 1:37 And the two disciples heard him speak, and they followed Jesus.
John 1:38 And Jesus turned, and beheld them following, and saith unto them, What seek ye? And they said unto him, Rabbi (which is to say, being interpreted, Teacher), where abideth thou?
Study Lenses
The verse centers on "looked", "upon", "jesus", "walked", "saith", "behold", and "lamb". It is saying that the verse draws attention to "looked" and "upon", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 35's "Again on the morrow John was standing..." into verse 37's "And the two disciples heard him speak...", so "looked" and "upon" 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 "looked" and "upon" with trust shaped by these words, not by a vague optimism outside the passage.