Verses with the word instant in the New Testament (4 verses):

Luke 2:38
And she coming in that instant gave thanks likewise unto the Lord, and spake of him to all them that looked for redemption in Jerusalem.

Luke 23:23
And they were instant with loud voices, requiring that he might be crucified. And the voices of them and of the chief priests prevailed.

Romans 12:12
Rejoicing in hope; patient in tribulation; continuing instant in prayer;

2 Timothy 4:2
Preach the word; be instant in season, out of season; reprove, rebuke, exhort with all longsuffering and doctrine.