when he had leisure to think and reflect upon his sins and transgressions, and when he was clear of all company, and no one could hear or see him, nor interrupt him in the vent of his sorrow, and when his disease might be heavier upon him, as some diseases increase in the night season: this may also be mystically understood, of a night of spiritual darkness and desertion, when a soul is without the discoveries of the love of God, and the influences of his grace; and has lost sight of God and Christ, and interest in them, and does not enjoy communion with them; and throughout this night season weeping endures, though joy comes in the morning.
And it may be applicable to David's antitype, to the doleful night in which he was betrayed, when it was the hour and power of darkness, and when he had no other couch or bed but the ground itself; which was watered, not only with his tears, but with his sweat and blood, his sweat being as it were great drops of blood falling to the ground; so he is often said to sigh and groan in spirit, Mr 7:34.
See the latter in Homer. Odyss 17. v. 110. Odyss. 19.