I. The first day of the week, or the Lord’s day, is to be set apart unto the ends of a holy rest unto God, by every one, according as his natural strength will enable him to employ himself in his lawful occasions any other day of the week.
There is no such certain standard or measure for the observance of the duties of this day, as that every one who exceeds it should by it be cut short, or that those who, on important reasons, come short of it should be stretched out thereunto. As God provided, in his services of old, that he who was not able to offer a bullock might offer a dove, with respect unto their outward condition in the world; so here there is an allowance also for the natural temperaments and abilities of men. Only, whereas if persons of old had pretended poverty, to save their charge in the procuring of an offering, it would not have been acceptable, yea, they would themselves have fallen under the curse of the deceiver; so no more will now a pretence of weakness or natural inability be any excuse unto any for neglect or profaneness. Otherwise, God requires of us, and accepts from us, “according to what we have, and not according to what we have not.” And we see it by experience, that some men’s natural spirits will carry them out unto a continuance in the outward observance of duties much beyond, nay, double perhaps unto what others are able, who yet may observe a holy Sabbath unto the Lord with acceptation. And herein lies the spring of the accommodation of these duties to the sick, the aged, the young, the weak, or persons any way distempered. “God knoweth our frame, and remembereth that we are dust;” as also that that dust is more discomposed and weakly compacted in some than in others. As thus the people gathered manna of old, some more, some less, אִישׁ לְפִי־אָכְלוֹ, “every man according to his appetite,” yet “he that gathered much had nothing over, and he that gathered little had no lack,” Exod. 16:17, 18; so is every one in sincerity, according to his own ability, to endeavour the sanctifying of the name of God in the duties of this day, not being obliged by the examples or prescriptions of others, according to their own measures.
~John Owen, An Exposition of the Epistle to the Hebrews, ed. W. H. Goold, vol. 19, Works of John Owen (Edinburgh: T&T Clark, 1862), 443–444.
Source: http://www.puritanboard.com/showthread.php/90810-Physical-Rest-on-the-Lord-s-Day, Comment #35