emblepō

The word is built from the ordinary word for seeing plus a small word meaning "in" or "onto", and the addition is the whole point: the look lands on one object and stays. Where the plain word for seeing (βλέπω) can cover sight in general, this one names the moment a person turns and aims the eyes at someone in particular.

In the Gospels that is almost always what it marks, and the pattern is hard to miss. Again and again the writers report that Jesus looked at the person in front of him, and then record what he said:

• He looks at the rich man who wants eternal life, and loves him (Mark 10:21).
• He looks at his disciples and tells them that what people cannot do, God can (Matthew 19:26; Mark 10:27).
• He looks at Simon and gives him a new name (John 1:42).
• He turns and looks at Peter in the courtyard, and Peter remembers what he had been told (Luke 22:61).

Nothing is said about the look itself. The writers simply record that it happened and let what follows carry the weight. It is not only Jesus who looks this way: John the Baptist looks at Jesus walking past and calls him the Lamb of God (John 1:36), and the servant girl in the high priest's courtyard looks straight at Peter before accusing him (Mark 14:67).

The same word can be aimed at a thing rather than a person. A crowd is told to look at the birds of the air and see how they are fed (Matthew 6:26), and the disciples stand with their eyes fixed on the sky after Jesus is taken from them (Acts 1:11). The core is the same in every case: the eyes are put on something on purpose.

Twice the word is not about aiming the eyes at anything but about whether the eyes work at all. When Jesus lays his hands a second time on the blind man at Bethsaida, the man's sight comes back and he can see everything clearly (Mark 8:25). When Paul retells what happened to him on the road to Damascus, he says the brightness of the light left him unable to see, so his companions had to lead him by the hand into the city (Acts 22:11).

English needs a word for sight here, not a word for looking, which is why translations move from "looked at" to "could see" and "could not see" without any signal that the same word lies underneath. The link to the first meaning is simple enough: a word for putting the eyes on something can be stretched to cover having eyes that can do it.