O Holy Apostles, intercede to our merciful God, that He may grant our souls forgiveness of sins.

Reading from the Synaxarion:

The Seventy Disciples and Apostles of our Lord Jesus Christ are those
Whom our Saviour chose in addition to the Twelve and sent forth unto
the work of preaching. With the passage of time, others were added to
their number by the Holy Apostles, who, with the accompaniment and
assistance of the Seventy, were preaching the Gospel of Christ in various
lands. Although their number eventually exceeded seventy, they were all
nonetheless referred to as "of the Seventy" out of reverence for the number
of Apostles which the Lord chose.The divine Apostle and Evangelist
Luke describes the calling and the sending forth of the Seventy as
follows in his Holy Gospel (Luke 10:1-16): "After these things the Lord
appointed another seventy disciples, and sent them two and two before His
face into every city and place, whither He Himself would come.
Therefore said He unto them, the harvest is great, but the labourers are
few: pray ye therefore the Lord of the harvest, that He send forth
labourers into His harvest. Go then: behold, I send you forth as lambs in
the midst of wolves. Carry neither purse, nor bag, nor sandals: and
greet no man on the way. And into whatsoever house ye enter first say,
Peace be on this house. And if the son of peace be there, your peace
shall rest upon it; if not, it shall turn to you again. And in the same
house remain, eating and drinking such things as they give: for the
labourer is worthy of his hire. Go not from house to house. And into
whatsoever city you enter, and they receive you, eat such things as are set
before you; And heal the sick that are therein, and say unto them, The
Kingdom of God is come nigh unto you. But into whatsoever city ye enter,
and they receive you not, go your ways out into the streets of the
same, and say, Even the very dust of your city, which cleaveeth on us,
we do wipe off against you: notwithstanding know ye this, that the
Kingdom of God is come nigh unto you. But I say unto you, that it shall
be more tolerable in that day for Sodom, than for that city. Woe
unto thee, Chorazin! woe unto thee, Bethsaida! for if the mighty works
had been done in Tyre and Sidon, which have been done in you, they
had a great while ago repented, sitting in sackcloth and ashes. But
it shall be more tolerable for Tyre and Sidon at the judgment, than
for you. And thou, Capernaum, which art exalted to heaven, shalt be
brought down to hades. He that heareth you heareth Me; and he that
despiseth you despiseth Me; and he that despiseth Me despiseth Him that
sent Me."After the Passion, Resurrection, and Ascension of our Lord,
and after Pentecost, on which all the Apostles and men and women
disciples of Christ, together with the Most Holy Theotokos (some 120 in
number), were gathered in the upper chamber, they received the grace of
the All-holy Spirit and went forth throughout the ends of the world,
everywhere preaching and teaching the Gospel of Christ, and leading to the
true Faith the peoples who were sunk in the darkness of impiety and
idolatry.

Apolytikion in the Third Tone
O Holy Apostles, intercede to our merciful God, that He may grant
our souls forgiveness of sins.

Kontakion in the Second Tone
With hymns let us praise the chorus of the Seventy disciples of
Christ, ye faithful; and in godliness, let us keep a feast, for we
learned through them to worship the Trinity, Who is indivisibly one; for
they are the lamps of our most godly Faith.