1 Corinthians 11:10

therefore the woman ought to be veil'd, out of regard to the angels.

Matthew 18:10

take care not to despise one of such an humble disposition: for I tell you, that in heaven their angels are continually attending the presence of my father who is in heaven:

Hebrews 1:14

are not all those spirits dispatch'd as ministers to take care of those who shall belong to the christian church.

Treasury of Scripture Knowledge

Summary

For this cause ought the woman to have power on her head because of the angels.

Bible References

Because

Matthew 18:10
take care not to despise one of such an humble disposition: for I tell you, that in heaven their angels are continually attending the presence of my father who is in heaven:
Hebrews 1:14
are not all those spirits dispatch'd as ministers to take care of those who shall belong to the christian church.