C. F. Keil and Franz Delitzsch on Leviticus 19:1

Lev 19:1

Holiness of Behaviour Towards God and Man. - However manifold the commandments, which are grouped together rather according to a loose association of ideas than according to any logical arrangement, they are all linked together by the common purpose expressed in Lev 19:2 in the words, “Ye shall be holy, for I am holy, Jehovah your God.” The absence of any strictly logical arrangement is to be explained chiefly from the nature of the object, and the great variety of circumstances occurring in life which no casuistry can fully exhaust, so that any attempt to throw light upon these relations must consist more or less of the description of a series of concrete events.

The commandment in Lev 19:2, “to be holy as God is holy,” expresses on the one hand the principle upon which all the different commandments that follow were based, and on the other hand the goal which the Israelites were to keep before them as the nation of Jehovah.