ὅτανhótan

whenever (implying hypothesis or more or less uncertainty); also causatively (conjunctionally) inasmuch as

Greek (New Testament) · G3752

Meanings

1. properly, whenever

(a) with subjunctive praes.: Matthew 6:2, Matthew 6:5, Mark 14:7, Luke 11:36, John 7:27, Acts 23:35, 1 Corinthians 3:4, and elsewhere; ἕως τ. ἡμέρας ἐκείνης, ὅ., Matthew 26:29, Mark 14:25; followed by τότε, 1 Thessalonians 5:3

2. As in Hom., but not in classical Greek prose, with indicative, when: with imperfect, Mark 3:11(cf. Genesis 38:9, and elsewhere); with praes., Mark 11:25; with future, Revelation 4:9; with aorist, Mark 11:19, Revelation 8:1.

Appears 123 times in the Bible.

Matthew 5:11 “God blesses you when people mock you and persecute you and lie about you and say all sorts of evil things against you because you are my followers.
Matthew 6:2 When you give to someone in need, don’t do as the hypocrites do—blowing trumpets in the synagogues and streets to call attention to their acts of charity! I tell you the truth, they have received all the reward they will ever get.
Matthew 6:5 “When you pray, don’t be like the hypocrites who love to pray publicly on street corners and in the synagogues where everyone can see them. I tell you the truth, that is all the reward they will ever get.
Matthew 6:6 But when you pray, go away by yourself, shut the door behind you, and pray to your Father in private. Then your Father, who sees everything, will reward you.
Matthew 6:16 “And when you fast, don’t make it obvious, as the hypocrites do, for they try to look miserable and disheveled so people will admire them for their fasting. I tell you the truth, that is the only reward they will ever get.
Matthew 9:15 Jesus replied, “Do wedding guests mourn while celebrating with the groom? Of course not. But someday the groom will be taken away from them, and then they will fast.

See every passage

Source: G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), public domain.