An angel - An “angel” is a messenger sent from God. See the notes at Matthew 1:20. It had now been about 400 years since the time of “Malachi,” and since there had been any divine revelation. During that time the nation was looking for the Messiah, but still with nothing more than the ancient prophecies to direct them. Now that he was about to appear, God sent his messenger to announce his coming, to encourage the hearts of his people, and to prepare them to receive him.
On the right side ... - The altar of incense stood close by the veil which divided the holy place from the most holy. On the north stood the table of showbread; on the south the golden candlestick. As Zechariah entered, therefore, with his face to the west, the angel would stand on the north, or near the table of showbread. That table was 18 inches square and 3 feet high. The top, as well as the sides and horns, was overlaid with pure gold, and it was finished around the upper surface with a crown or border of gold. Just below this border, four golden rings were attached to each side of the altar, one near each corner. The staves or rods for bearing the altar passed through these rings, and were made of the same wood with the altar itself, and richly overlaid with the same precious metal. Upon this altar incense was burned every morning and every evening, so that it was literally perpetual, Exodus 30:8. Neither burnt-sacrifice, nor meat-offering, nor drink-offering was permitted upon this altar; nor was it ever stained with blood except once annually, when the priest made atonement, Leviticus 16:18-19.