John 12:36

34 The crowd replied, “We have heard from the Law that the Christ will remain forever. So how can you say that the Son of Man must be lifted up? Who is this Son of Man?”

35 Then Jesus told them, “For a little while longer, the Light will be among you. Walk while you have the Light, so that darkness will not overtake you. The one who walks in the darkness does not know where he is going.

While you have the Light, believe in the Light, so that you may become sons of light.” After Jesus had spoken these things, He went away and was hidden from them.

37 Although Jesus had performed so many signs in their presence, they still did not believe in Him.

38 This was to fulfill the word of Isaiah the prophet: “Lord, who has believed our message? And to whom has the arm of the Lord been revealed?”

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
While you have the Light, believe in the Light, so that you may become sons of light.” After Jesus had spoken these things, He went away and was hidden from them.
KJV
While ye have light, believe in the light, that ye may be the children of light. These things spake Jesus, and departed, and did hide himself from them.
WEB
While you have the light, believe in the light, that you may become children of light.” Jesus said these things, and he departed and hid himself from them.
ASV
While ye have the light, believe on the light, that ye may become sons of light. These things spake Jesus, and he departed and hid himself from them.
DARBY
While ye have the light, believe in the light, that ye may become sons of light. Jesus said these things, and going away hid himself from them.
BLB
While you⁺ have the Light, believe in the Light, so that you⁺ may become sons of light.” Jesus spoke these things, and having gone away, He was hidden from them.
ÅB
Tro på lyset den stund dere har lyset, for at dere kan bli lysets barn! Dette talte Jesus, og han gikk bort og skjulte seg for dem.
OTB
Tro på lyset mens dere har lyset, så dere kan bli lysets barn." Da han hadde sagt dette, forlot Jesus dem og skjulte seg for dem.
B1930
Tro på lyset den stund I har lyset, forat I kan bli lysets barn! Dette talte Jesus, og han gikk bort og skjulte sig for dem.

Study notes (Tyndale)

Original text and word study

Cross references