{Had been instructed in the way of the Lord} ((886e)
kat(8863)h(886d)enos t(886e) hodon tou kuriou). Periphrastic past perfect
passive of kat(8863)he(935c), rare in the old Greek and not in the LXX
from kata and (8863)he(935c) ((8863)h(935c), sound) as in  Lu 1:4 , to
re-sound, to re-echo, to teach by repeated dinning into the ears
as the Arabs do now, to teach orally by word of mouth (and ear).
Here the accusative of the thing (the word) is retained in the
passive like with didask(935c), to teach (Robertson, _Grammar_, p.
485). Being fervent in spirit (ze(936e) t(9369) pneumati). Boiling
(from ze(935c), to boil, old and common verb, in N.T. only here and
 Ro 12:11 ) like boiling water or yeast. The Latin verb _ferveo_
means to boil or ferment. Locative case after it. {Taught
carefully} (edidasken akrib(9373)). Imperfect active, was teaching
or inchoative, began teaching, accurately. He taught accurately
what he knew, a fine gift for any preacher. {Only the baptism of
John} (monon to baptisma I(9361)nou). It was a {baptism of
repentance} (marked by repentance) as Paul said ( 13:24  19:4 ),
as Peter said ( 2:38 ) and as the Gospels tell ( Mr 1:4 , etc.).
That is to say, Apollos knew only what the Baptist knew when he
died, but John had preached the coming of the Messiah, had
baptized him, had identified him as the Son of God, had
proclaimed the baptism of the Holy Spirit, but had not seen the
Cross, the Resurrection of Jesus, nor the great Day of Pentecost.