She makes trivial excuses, as one in a dream.

I have put off my coat - The bride must have been in a dream or in much disorder of mind to have made the frivolous excuses here mentioned. The words relate to the case of a person who had gone to take rest on his bed. As they wore nothing but sandals, they were obliged to wash their feet previously to their lying down. I have washed my feet, taken off my clothes, and am gone to bed: I cannot therefore be disturbed. A Hindoo always washes his feet before he goes to bed. If called from his bed, he often makes this excuse, I shall daub my feet; and the excuse is reasonable, as the floors are of earth; and they do not wear shoes in the house - Ward.

I have put off my (d) coat; how shall I put it on? I have washed my feet; how shall I defile them?
(d) The spouse confesses her nakedness, and that of herself she has nothing, or seeing that she is once made clean she promises not to defile herself again.

I have put off my coat,.... In order to lie down on her bed at night, and take her ease; meaning her conversation garments, which she had not been careful of to keep, but had betook herself to carnal ease and rest, and was off her watch and guard, Nehemiah 4:23; and being at ease, and free from trouble, affliction, and persecution, was unwilling to arise and go with her beloved, lest she should meet with the same trials and sufferings as before, for the sake of him and his Gospel; which may be greatly the sense of her next words;
how shall I put it on? which suggests an apprehension of difficulty in doing it, it being easier to drop the performance of duty than to take it up again; and shows slothfulness and sluggishness, being loath and not knowing how to bring herself to it; and an aversion of the carnal and fleshly part unto it; yea, as if she thought it was unreasonable in Christ to desire it of her, when it was but her reasonable service; or as if she imagined it was dangerous, and would be detrimental to her rest, and prejudicial to her health;
I have washed my feet; as persons used to do when come off of a journey, and about to go to bed (e), being weary; as she was of spiritual exercises, and of the observance of ordinances and duties, and so betook herself to carnal ease, and from which being called argues,
how shall I defile them? by rising out of bed, and treading on the floor, and going to the door to let her beloved in; as if hearkening to the voice of Christ, obeying his commands, and taking every proper step to enjoy communion with him, would be a defiling her; whereas it was the reverse of these that did it: from the whole it appears, that not only these excuses were idle and frivolous, but sinful; she slighted the means Christ made use of to awaken her, by calling and knocking; she sinned against light and knowledge, sleeping on, when she knew it was the voice of her beloved; she acted a disingenuous part in inviting Christ into his garden, and then presently fell asleep; and then endeavoured to shift the blame from herself, as if she was no ways culpable, but what was desired was either difficult, or unreasonable, or unlawful; she appears guilty of great ingratitude, and discovers the height of folly in preferring her present ease to the company of Christ.
(e) Homer. Odyss. 19. v. 317.

Trivial excuses (Luke 14:18).
coat--rather, the inmost vest, next the skin, taken off before going to bed.
washed . . . feet--before going to rest, for they had been soiled, from the Eastern custom of wearing sandals, not shoes. Sloth (Luke 11:7) and despondency (Deuteronomy 7:17-19).

3 I have put off my dress,
How shall I put it on again?
I have washed my feet,
How shall I defile them again?
She now lies unclothed in bed. כּתּנת is the χιτών worn next to the body, from כתן, linen (diff. from the Arab. ḳuṭun, cotton, whence French coton, calico = cotton-stuff). She had already washed her feet, from which it is supposed that she had throughout the day walked barefooted, - how (איככה, how? both times with the tone on the penult.;
(Note: That it has the tone on the penult., like כּכה, e.g., Song 5:9, is in conformity with the paragog. nature of .ה The tone, however, when the following word in close connection begins with ,א goes to the ult., Esther 7:6. That this does not occur in איך אל, is explained from the circumstance that the word has the disjunctive Tifcha. But why not in איך אט? I think it is for the sake of the rhythm. Pinsker, Einl. p. 184, seeks to change the accentuation in order that the penult. accent might be on the second איך, but that is not necessary. Cf. Psalm 137:7.)
cf. איכה, where ? Song 1:7) should she again put on her dress, which she had already put off and laid aside (פּשׁט)? why should she soil (אטנּפם, relating to the fem. רגלי, for אטנפן) again her feet, that had been washed clean? Shulamith is here brought back to the customs as well as to the home of her earlier rural life; but although she should thus have been enabled to reach a deeper and more lively consciousness of the grace of the king, who stoops to an equality with her, yet she does not meet his love with an equal requital. She is unwilling for his sake to put herself to trouble, or to do that which is disagreeable to her. It cannot be thought that such an interview actually took place; and yet what she here dreamed had not only inward reality, but also full reality. For in a dream, that which is natural to us or that which belongs to our very constitution becomes manifest, and much that is kept down during our waking hours by the power of the will, by a sense of propriety, and by the activities of life, comes to light during sleep; for fancy then stirs up the ground of our nature and brings it forth in dreams, and thus exposes us to ourselves in such a way as oftentimes, when we waken, to make us ashamed and alarmed. Thus it was with Shulamith. In the dream it was inwardly manifest that she had lost her first love. She relates it with sorrow; for scarcely had she rejected him with these unworthy deceitful pretences when she comes to herself again.

My coat - My day clothes, as persons use to do when they go to rest. How - It is inconvenient and troublesome to do it at this time. Washed my feet - Which the eastern people commonly did when they went to bed.