As I am making my Robinson-Pierpont edition of the gospel of Matthew, I am editing my eclectic edition here and there. During this process I found a Byzantine reading that I think is the original text rather than what I previously had in my eclectic text and is found in the NA28.

Matt 21:25 παρ εαυτοις ℵ C D E W Σ Φ 0102 0233 𝔐 TR RP TH ‖ εν εαυτοις B L Z Cyr SBL NA28 {\} ‖ lac A N P 0281.

The reading with παρ has strong support.  I immediately thought that since εν εαυτοις is a very common phrase in the gospels, and παρ εαυτοις is not, it is far more likely that scribes would write εν εαυτοις automatically unconsciously, than the other way around.  So I changed my text to the παρ εαυτοις reading, and this was before I looked up the Tyndale House reading and saw that they follow that reading.  The preposition παρα with the dative case answers the question “where.”  They were “by” themselves, which implies separation for privacy; thus, “away by themselves.” You can download my eclectic edition of Matthew’s gospel here.