54 The words “against him” are implied, as suggested by L&N 30.71.
55 Or “guarding.” This is a negative term in Luke-Acts (Luke 6:7; 14:1; 20:20).
56 The word πύλη (pulē) may refer to a house door or gate, or to the large gates used in a palace, temple, or city wall. Here the context clearly indicates a reference to the latter, so the translation “city gates” is used.

In other versions

but their plot became known to Saul. They were watching the gates day and night in order to kill him,

but Saul learned of their plan. Day and night they kept close watch on the city gates in order to kill him.

but Saul learned of their plot. So they were watching the gates day and night intending to kill him,

They were watching for him day and night at the city gate so they could murder him, but Saul was told about their plot.

But their plot became known to Saul, and they were also watching the gates both day and night so that they could do away with him.

But their laying await was known of Saul. And they watched the gates day and night to kill him.

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