{Regardeth} (phronei). "Thinks of," "esteems," "observes,"
"puts his mind on" (from phr(886e), mind). The Textus Receptus has
also "he that regardeth not," but it is not genuine. {Unto the
Lord} (kuri(9369)). Dative case. So as to 	(9369) the(9369) (unto God).
He eats unto the Lord, he eats not unto the Lord. Paul's
principle of freedom in non-essentials is most important. The
Jewish Christians still observed the Seventh day (the Sabbath).
The Gentile Christians were observing the first day of the week
in honour of Christ's Resurrection on that day. Paul pleads for
liberty.