These (144,000) are the ones who have not been defiled with women, for they have kept themselves CHASTE.
These (144,000) are the ones who have not been defiled with women, for they have kept themselves CHASTE.
If we interpret this symbolically, then
Being CHASTE is one of the most difficult of human endeavors. The force to replenish the earth (Genesis 1:28) was created into us. Thus, when false doctrines want to subvert a true believer (or these 144,000), they will attack the vulnerabilities with something like "forbidding marriage" (and allowing anything to go - 1 Timothy 4:3).
Contrast this with Hebrews 13:4.
These (144,000) are the ones who FOLLOW THE LAMB wherever HE goes.
Here we see a role reversal from John's "Good Shepherd" discussion in John 10:1-18 and John 21:22. There is a price to pay to follow (Matthew 16:24; John 12:26), and hence the use of "PURCHASE" in the next sentence in the verse.
Contrast this with following the MOTHER OF HARLOTS (Revelation 17:5)!
These (144,000) have been PURCHASED from among men as FIRST-FRUITS to GOD and to THE LAMB.
PURCHASED is past tense, so many scholars try to determine when they were purchased. Finis Jennings Dake implies that these are the first 144,000 in the early New Testament church who meet the requirements of this and the following verse.
In the Middle Ages, these 144,000 were thought to be priests.
However, FIRST-FRUITS are associated with reaping. Reaping has three parts:
Later in this chapter in verse 15, the harvest will take place. This implies that these 144,000 are FIRST-FRUITS after "the rapture" and within the Tribulation.
During the Church age, Christ is the FIRST-FRUIT (1 Corinthians 15:23). He was presented as such in the temple in Luke 2:23. But these 144,000 are post Church Age and thus have a song we cannot learn (previous verse).
An interesting observation (which does not have direct Scripture to support it):
At the time of "the rapture", if a person believes that children up to the "age of accountability" are without sin, then fetuses and children through this "age of accountability" will also be "raptured". Mothers will become unpregnant and day care centers will notice a lot of children missing. However, mankind, being as it is, will still procreate after "the rapture". The devil will realize that these children "are blameless" (next verse) and are a threat to his total dominance, so he will try to eliminate them through abortions and "mercy killings". This would be a mirroring of what Herod tried to do after Christ was born - Matthew 2:16. These may be the 144,000 PURCHASED from among men.