Everybody, once the terms are defined, agrees that the Lord’s Church has “functions” to express and to enjoy: worship, holiness, faith, grace, freedom, prayer, teaching, evangelizing, praising, caring for the poor, etc., etc.
The problem comes with “forms”, that is, the way the functions are to be expressed or accomplished.
By definition and by their very nature functions are unchangeable and remain the same because they are the eternal substance but forms change and are changeable because they are temporary. This truth is borne out by the diversity of forms expressing unchangeable functions throughout biblical history (e.g. worshipping at altars, temples, in Jerusalem and in the Mountain. This distinction is noted many places in the NT, e.g. Romans 14/Galatians 2).
For example, every genuine believer from his/her heart worships-the eternal function. But not all who worship expresses it the same way- various forms: eyes closed/eyes open, head bowed/head raised, standing/kneeling, hands raised/hands passive, clapping/not clapping, accapella/instrumental, this place/that place, etc., etc., ad infinite um. The same can be said of the Lord’s Supper; the memorial is the function. Method of partaking may be/has been varied in it forms.
“Obedience to God’s Law/Commands is not to be, indeed cannot be, achieved by ‘legalistic law-keeping’ but by a ‘loving response’ that results in a gracious life-style that is accomplished by Grace.”