The Spirit of God was on them:
The promises of the outpouring of the Spirit like in Joel, is a continuous blessing of God, which has an en emphatic but not exclusive fulfillment in the new covenant, Acts 2.
[Joel 2:28] "And it shall come to pass afterward, that I will pour out my Spirit on all flesh; your sons and your daughters shall prophesy, your old men shall dream dreams, and your young men shall see visions.
[ESV 1Sam 10:5-7]
5After that you shall come to Gibeath-elohim, where there is a garrison of the Philistines. And there, as soon as you come to the city, you will meet a group of prophets coming down from the high place with harp, tambourine, flute, and lyre before them, prophesying. 6Then the Spirit of the LORD will rush upon you, and you will prophesy with them and be turned into another man. 7Now when these signs meet you, do what your hand finds to do, for God is with you.
Jewish Encyclopedia: Shekinah (Holy Spirit)
Those on Whom the Shekinah Rested.
The Shekinah was one of the five things lacking in the Second Temple
(Targ. to Hag. i. 8; Yer. Ta'an. 65a, and parallel passages). Shunning
the Gentiles, it rested solely among the Israelites (Shab. 22b), and
even there only when they numbered at least 2,002 myriads (Ber. 7a;
Yeb. 64a; B. B. 15b; comp. Sanh. 105b), confining itself solely to
those of this multitude who were of pure and therefore aristocratic
lineage (Ḳid. 70b) and who were wise, brave, wealthy, and tall (Shab.
92a; comp. Ned. 38a); but even for such it would not descend into an
atmosphere of sadness (Shab. 30b and parallel passages), since there
can be no sorrow in the presence of God (Ḥag. 5b); nor should one pray
in a sorrowful frame of mind (Ber. 31a).
The polemic attitude which the conception of the Shekinah betrays
toward the founder and the ideal of Christianity is unmistakable. The
Shekinah rested upon the priests even if they were unclean (Yoma 56b);
and if it was lacking, none approached them for an oracle (ib. 75b).
Prominent doctors of the Law were considered worthy of the Shekinah,
but both their generation. (i.e., their contemporaries) and their
place of residence (i.e., in a foreign land) deprived them of its
presence (Suk. 28a; B. B. 60a; Soṭah 48b; M. Ḳ. 25a). In all these
statements the Shekinah is identical with the Holy Spirit. It was
received by thirty-six pious persons (Suk. 45b), a number which
recalls the thirty-six nomes of Egypt and their gods. The Shekinah was
also believed to be a protection, as is still the case in the night
prayer: "on my four sides four angels, and above my head the Shekinah
of God" (comp. Ḳid. 31a). The Shekinah is found at the head of the
sick (Shab. 12b) and at the right hand of man (Targ. to Ps. xvi. 8).
Pharaoh's daughter saw it at the side of Moses (Soṭah 11a; comp. Targ.
to Judges vi. 13), and it spoke with the prophet Jonah twice (Zeb.
98a), with Adam, with the serpent (Bek. 8a; Shab. 87a; Pes. 87b et
passim), and with others.
To Whom Does the Shekinah Appear?
Unsullied thoughts and pious deeds render one worthy of the Shekinah,
which is present when two are engaged with the Torah (Ab. iii. 3),
when ten pray (Ber. 6a; Ab. 3, 9), and when the mysticism of the
Merkabah is explained (Ḥag. 14b); and it is likewise attracted by the
study of the Law at night (Tamid 32b); the reading of the "Shema'"
(Shab. 57a); prayer (B. B. 22a); hospitality (Shab. 127a; Sanh. 103b);
benevolence (B. B. 10a); chastity (Derek Ereẓ i.); peace and
faithfulness in married life (Soṭah 17a); and similar deeds and
qualities (Ket. 111a; Ber. 67a; Men. 43b; Sanh. 42b; Yer. Ḥag. i. et
passim). Sins, on the other hand, cause the Shekinah to depart (Targ.
to Isa. lvii. 7; Jer. xxxiii. 5 et passim). It inspires correct
judgment in upright judges (Sanh. 7a), while unrighteous magistrates
cause it to depart (Shab. 139a). It appeared on the day on which the
Tabernacle was first erected (Num. R. xiii.). Before the Israelites
sinned the Shekinah rested on every one; but when they did evil it
disappeared (Soṭah 3b). In like manner it departed from David when he
became leprous (Sanh. 107a). Among the transgressions which have this
result are the shedding of blood (Yoma 84b) and idolatry, (Meg. 15b;
others are cited in Soṭah 42a; Kallah, end; Ber. 5b, 27b; Shab. 33a;,
and Sanh. 106a). Whosoever sins in secret or walks with a proud and
haughty bearing "crowds out the feet of the Shekinah" (Ḥag. 16a; Ber.
43b; comp. ib. 59a).
The Holy Spirit or "Divine Presense", Shekinah rested upon them
Legends of the Jews 2:1:91 Seeing that the Shekinah rested upon him,
Potiphar treated Joseph not as a slave, but as a member of his family,
for he said, "This youth is not cut out for a slave's work, he is
worthy of a prince's place.
The Legends of the Jews by Louis Ginzberg 
Targum Jonathan on Exodus 40:35 And Mosheh was not able to enter the
tabernacle of ordinance, because the Cloud of Glory rested upon it,
and the glory of the Lord's Shekinah filled the tabernacle.
The Targum of Jonathan ben Uzziel, trans. J. W. Etheridge, London, 1862
Sefer HaIkkarim, Maamar 3 25:14 The Shekinah or holy spirit rested
upon Israel through the offerings, and the priest foretold the future
through the Urim and Thummim, as the senses testified.
Sefer Ha-ikkarim, Jewish Publication Society of America, 1929
And the so-called Trinity, was already believed by the Church of Israel, before Jesus.
"Hear, O Israel, Adonai Eloheinu Adonai is one. These three are one.
How can the three Names be one? Only through the perception of faith;
in the vision of the Holy Spirit, in the beholding of the hidden eye
alone.…So it is with the mystery of the threefold Divine
manifestations designated by Adonai Eloheinu Adonai—three modes which
yet form one unity." 1
Zohar II:43b (vol. 3, p. 134 in the Soncino Press edition).
A Christian quote? Hardly. The above is taken from the Zohar, an
ancient book of Jewish mysticism. The Zohar is somewhat esoteric and
most contemporary Jewish people don't study it, but there are other
Jewish books that refer to God's plurality as well.