New Revised Standard Version
When Aaron saw this, he built an altar before it; and Aaron made proclamation and said, “Tomorrow shall be a festival to the LORD.”

Contemporary English Version
When Aaron saw what was happening, he built an altar in front of the idol and said, "Tomorrow we will celebrate in honor of the LORD."

New American Bible
On seeing this, Aaron built an altar in front of the calf and proclaimed, “Tomorrow is a feast of the LORD.”

Douay-Rheims Bible
And when Aaron saw this, he built an altar before it, and made proclamation by a crier's voice, saying To morrow is the solemnity of the Lord.

And when Aaron saw this, he built an altar before it, and made proclamation by a crier's voice, saying To morrow is the solemnity of the Lord.

Aaron

1 Samuel 14:35 And Saul built an altar to the Lord: and he then first began to build an altar to the Lord.

2 Kings 16:11 And Urias, the priest, built an altar according to all that king Achaz had commanded from Damascus so did Urias, the priest, until king Achaz came from Damascus.

Hosea 8:11,14 Because Ephraim hath made many altars to sin: altars are become to him unto sin. . . .

made proclamation

Leviticus 23:2,4,21,37 Speak to the children of Israel, and thou shalt say to them: These are the feasts of the Lord, which you shall call holy. . . .

1 Kings 21:9 And this was the tenor of the letters: Proclaim a fast, and make Naboth sit among the chief of the people;

2 Kings 10:20 And he said: Proclaim a festival for Baal. And he called,

2 Chronicles 30:5 And they decreed to send messengers to all Israel from Bersabee even to Dan, that they should come, and keep the phase to the Lord the God of Israel in Jerusalem: for many had not kept it as it is prescribed by the law.

a feast

Exodus 32:4 And when he had received them, he fashioned them by founders' work, and made of them a molten calf. And they said: These are thy gods, O Israel, that have brought thee out of the land of Egypt.

Exodus 10:9 Moses said: We will go with our young and old, with our sons and daughters, with our sheep and herds: for it is the solemnity of the Lord our God.

Exodus 12:14 And this day shall be for a memorial to you; and you shall keep it a feast to the Lord in your generations, with an everlasting observance.

1 Kings 12:32,33 And he appointed a feast in the eighth month, on the fifteenth day of the month, after the manner of the feast that was celebrated in Juda. And going up to the altar, he did in like manner in Bethel, to sacrifice to the calves, which he had made: and he placed in Bethel priests of the high places, which he had made. . . .

1 Corinthians 5:8 Therefore, let us feast, not with the old leaven, nor with the leaven of malice and wickedness: but with the unleavened bread of sincerity and truth.