εὐφραίνω

Luke 12:19 εὐφραίνου. do be merry.

Then I will say to myself, “You have plenty of good things laid up for many years. Take it easy. Eat, drink, and be merry!”’

Here: A present imperative in middle/passive form: 'keep enjoying yourself,' 'keep celebrating.' The word often describes festive banqueting. Luke uses it for the feast over the returned son (15:23–32) and for the rich man who 'feasted sumptuously every day' (16:19).

Luke 15:23 εὐφρανθῶμεν, let us be merry,

Bring the fattened calf and kill it. Let us feast and celebrate.

Here: 'Let us celebrate!' This is a 'let us' form, so the father includes himself and the whole household. It means festive joy expressed in feasting, music and company (compare 'music and dancing' in v. 25). It is the key word of the parable's ending (vv. 24, 29, 32).

Luke 15:24 εὐφραίνεσθαι.¶ to be merry.

For this son of mine was dead and is alive again! He was lost and is found!’ So they began to celebrate.

Here: Present tense: an ongoing celebration. In Luke this word goes with banquets: food, music and dancing (15:25), the same verb as 'let us feast and celebrate' in v.23.

Luke 15:29 εὐφρανθῶ. I may make merry.

But he answered his father, ‘Look, all these years I have served you and never disobeyed a commandment of yours. Yet you never gave me even a young goat so I could celebrate with my friends.

Here: 'That I might make merry', meaning to feast and celebrate. It is the same verb as the father's celebration (vv. 23, 24, 32). He wants the same joy, but on his own terms and as a reward he has earned.

Luke 15:32 εὐφρανθῆναι To make merry

But it was fitting to celebrate and be glad, because this brother of yours was dead and is alive again; he was lost and is found.’”

Here: Festive celebration with food, music and dancing (v. 25). It comes first in the sentence for emphasis. It answers the elder son's complaint in v. 29 that he was never given a goat 'so that I might celebrate' (same verb) with his friends.

Luke 16:19 εὐφραινόμενος making good cheer

Now there was a rich man dressed in purple and fine linen, who lived each day in joyous splendor.

Here: 'Making merry', especially by feasting. In Luke it is the word for the rich fool's 'eat, drink, be merry' (12:19) and for the father's feast for the returning son (15:23–32). Present participle: this is ongoing, his steady state.

Acts 2:26 ηὐφράνθη was glad

Therefore my heart is glad and my tongue rejoices; my body also will dwell in hope,

Here: 'Was gladdened' or 'became glad'. The word is passive in form, but here it simply means gladness that wells up. In the Greek Old Testament it is the usual translation of Hebrew samach, the joy of feasts and festivals. The past tense copies the Hebrew of the psalm, which describes a settled state, so English can fairly say 'is glad' or 'was glad'.

Acts 7:41 εὐφραίνοντο they were rejoicing

At that time they made a calf and offered a sacrifice to the idol, rejoicing in the works of their hands.

Romans 15:10 εὐφράνθητε do rejoice you

Again, it says: “Rejoice, O Gentiles, with His people.”

Here: A command to many people: 'celebrate!' The word means festive, shared joy, the joy of feasts, songs and banquets, not a private mood. The form is grammatically passive but means simply 'be glad / rejoice'.

2 Corinthians 2:2 εὐφραίνων gladdening

For if I grieve you, who is left to cheer me but those whom I have grieved?

Galatians 4:27 εὐφράνθητι do rejoice

For it is written: “Rejoice, O barren woman, who bears no children; break forth and cry aloud, you who have never travailed; because more are the children of the desolate woman than of her who has a husband.”

Here: A command to celebrate. The word carries the feel of festive, public joy, as at a feast, and is more than private contentment.

Revelation 11:10 εὐφραίνονται does make merry

And those who dwell on the earth will gloat over them and celebrate and send one another gifts, because these two prophets had tormented them.

Here: 'They make merry.' This is festive joy: feasting, drinking, a public celebration. It goes further than a feeling of gladness.

Revelation 12:12 εὐφραίνεσθε do rejoice

Therefore rejoice, O heavens, and you who dwell in them! But woe to the earth and the sea; with great fury the devil has come down to you, knowing he has only a short time.”

Here: A present-tense command, so the sense is "keep celebrating". The word is used for festival and banquet joy, not just an inner feeling of gladness.

Revelation 18:20 εὐφραίνου do rejoice

Rejoice over her, O heaven, and you saints and apostles and prophets, because God has pronounced for you His judgment against her.

Here: A present-tense command: 'be celebrating, keep up the festivity'. The word suggests festive gladness, even a feast, and stands in deliberate contrast to the weeping and dust-throwing of the mourners in verses 9–19.