The number 3 in the Bible means these "3" things: divine wholeness, completeness and perfection.
3 confirms a matter.
God's attributes are 3: omniscience, omnipresence, and omnipotence.
On the third day, the earth rose from the water, symbolic of resurrection life.
And lest we forget the Father, the Son, and the Holy Spirit.
But also- We have a human habit of looking for patterns of 3. You hear people say all the time expressions like “three’s company” or “three’s a crowd” or “the third time’s the charm,” or “bad news (or deaths) always comes in threes.” So I would not be so quick to think that all the 3's in the Bible were supposed to be Holy. Maybe it was just people writing in that pattern.