(17) Pray without ceasing.—Theophylact well says, “This shows the way to ‘rejoice always’—to wit, incessant prayer and eucharist, for he that has accustomed himself to hold converse with God, and to give thanks to Him over everything that happens as happening well, will evidently have unbroken joy.” Though a man cannot be incessantly praying in words, the mind may be held continuously in an attitude of prayer, even in sleep (Song of Solomon 5:2).

5:16-22 We are to rejoice in creature-comforts, as if we rejoiced not, and must not expect to live many years, and rejoice in them all; but if we do rejoice in God, we may do that evermore. A truly religious life is a life of constant joy. And we should rejoice more, if we prayed more. Prayer will help forward all lawful business, and every good work. If we pray without ceasing, we shall not want matter for thanksgiving in every thing. We shall see cause to give thanks for sparing and preventing, for common and uncommon, past and present, temporal and spiritual mercies. Not only for prosperous and pleasing, but also for afflicting providences, for chastisements and corrections; for God designs all for our good, though we at present see not how they tend to it. Quench not the Spirit. Christians are said to be baptized with the Holy Ghost and with fire. He worketh as fire, by enlightening, enlivening, and purifying the souls of men. As fire is put out by taking away fuel, and as it is quenched by pouring water, or putting a great deal of earth upon it; so we must be careful not to quench the Holy Spirit, by indulging carnal lusts and affections, minding only earthly things. Believers often hinder their growth in grace, by not giving themselves up to the spiritual affections raised in their hearts by the Holy Spirit. By prophesyings, here understand the preaching of the word, the interpreting and applying the Scriptures. We must not despise preaching, though it is plain, and we are told no more than what we knew before. We must search the Scriptures. And proving all things must be to hold fast that which is good. We should abstain from sin, and whatever looks like sin, leads to it, and borders upon it. He who is not shy of the appearances of sin, who shuns not the occasions of it, and who avoids not the temptations and approaches to it, will not long keep from doing sin.Pray without ceasing - See the notes on Romans 12:12. The direction here may be fairly construed as meaning:

(1) That we are to be regular and constant in the observance of the stated seasons of prayer. We are to observe the duty of prayer in the closet, in the family, and in the assembly convened to call on the name of the Lord. We are not to allow this duty to be interrupted or intermitted by any trifling cause. We are so to act that it may be said we pray regularly in the closet, in the family, and at the usual seasons when the church prays to which we belong.

(2) we are to maintain an uninterrupted and constant spirit of prayer. We are to be in such a frame of mind as to be ready to pray publicly if requested; and when alone, to improve any moment of leisure which we may have when we feel ourselves strongly inclined to pray. That Christian is in a bad state of mind who has suffered himself, by attention to worldly cares, or by light conversation, or by gaiety and vanity, or by reading an improper book, or by eating or drinking too much, or by late hours at night among the thoughtless and the vain, to be brought into such a condition that he cannot engage in prayer with proper feelings. There has been evil done to the soul if it is not prepared for communion with God at all times, and if it would not find pleasure in approaching his holy throne.

17. The Greek is, "Pray without intermission"; without allowing prayerless gaps to intervene between the times of prayer. This is a means to maintain our rejoicing, and therefore next mentioned. Prayer is a making known our requests to God, Philippians 4:6. And it is either mental, in the heart only, as Hannah’s was; or vocal, expressed with the voice; or, as some add, vital: so good works have a voice to bring down blessings, as men’s sins cry for vengeance.

Without ceasing; not as the Euchites and Messalians of old, who hence thought no other duties were required, but always praying; but by the word in the text, is either meant a praying without fainting, as in the parable, Luke 18:1, and which the apostle calls a perseverance in prayer, Ephesians 6:18 Colossians 4:2; proskartereite, or praying with strength, as the Greek word there imports, and so not to faint; so Romans 12:12. Or a praying in every thing, as Philippians 4:6: In every thing let your requests be made known, & c. Or, in every season, as Ephesians 6:18; to take hold of the seasons of prayer. Or, in all seasons and times, whether good or bad, yet still to pray. And all this is meant by the word in the text, which is also used 1 Thessalonians 1:3 1 Thessalonians 2:13 Romans 1:9; and implies in general no more but a constant course of prayer, so Colossians 4:2, to watch unto prayer, as that the course of it be not interrupted by any diversions. As also to preserve a heart disposed to pray at all times, and to mingle ejaculatory prayers with the several actions of our lives: our wants are continual, and God will be acknowledged in all our supplies, and therefore we ought to pray continually.

Pray without ceasing. Not that saints should be always on their knees, or ever lifting up their hands, and vocally calling upon God; this is not required of them, and would clash with, and break in upon other parts of religious worship, and the duties of civil life, which are to be attended to, as well as this, and besides would be impracticable; for however willing a spiritual man might be to be engaged in this work always, yet the flesh is weak, and would not be able to bear it; and it requires food and drink, sleep and rest, for its refreshment and support; for all which there must be time allowed, as well as for other actions of animal life, and the business of a man's calling. But the meaning is, that believers should be daily, and often found in the performance of this duty; for as their wants daily return upon them, and they are called to fresh service, and further trials and exercises, they have need of more grace, strength, and assistance, and therefore should daily pray for it; and besides certain times both in the closet, and in the family, in which they should attend the throne of grace, there is such a thing as mental prayer, praying in the heart, private ejaculations of the soul, which may be sent up to heaven, while a man is engaged in the affairs of life. The Ethiopic version renders the words, "pray frequently"; do not leave off praying, or cease from it through the prevalence of sin, the temptations of Satan, or through discouragement, because an answer is not immediately had, or through carelessness and negligence, but continue in it, and be often at it; see Luke 18:1. These words are opposed to the practice of such, who either pray not at all, or, having used it, have left it off, or who only pray in a time of trouble and distress, and bear hard on those who think they should not pray but when under the influences of the Spirit, and when his graces are in a lively exercise: the reason for this rule of praying with frequency and constancy is, because the saints are always needy, they are always in want of mercies of one kind or another, and therefore should continually go to the throne of grace, and there ask for grace and mercy to help them in time of need. Pray without ceasing.