And call upon me in the day of trouble - This is a part of real religion as truly as praise is, Psalm 50:14. This is also the duty and the privilege of all the true worshippers of God. To do this shows where the heart is, as really as direct acts of praise and thanksgiving. The purpose of all that is said here is to show that true religion - the proper service of God - does not consist in the mere offering of sacrifice, but that it is of a spiritual nature, and that the offering of sacrifice is of no value unless it is accompanied by corresponding acts of spiritual religion, showing that the heart has a proper appreciation of the mercies of God, and that it truly confides in him. Such spirituality in religion is expressed by acts of praise Psalm 50:14; but it is also as clearly expressed Psalm 50:15 by going to God in times of trouble, and rolling the burdens of life on his arm, and seeking consolation in him.
I will deliver thee - I will deliver thee from trouble. This will occur
(a) either in this life, in accordance with the frequent promises of his word (compare the notes at Psalm 46:1); or
(b) wholly in the future world, where all who love God will be completely and forever delivered from all forms of sorrow.
And thou shalt glorify me - That is, Thou wilt honor me, or do me honor, by thus coming to me with confidence in the day of calamity. There is no way in which we can honor God more, or show more clearly that we truly confide in him, than by going to him when everything seems to be dark; when his own ways and dealings are wholly incomprehensible to us, and committing all into his hands.

And call upon me in the day of trouble,.... This is another part of spiritual sacrifice or worship, which is much more acceptable to God than legal sacrifices. Invocation of God includes all parts of religious worship, and particularly designs prayer, as it does here, of which God, and he only, is the object; and which should be performed in faith, in sincerity, and with fervency; and though it should be made at all times, in private and in public, yet more especially should be attended to in a time of affliction, whether of soul or body, whether of a personal, family, or public kind, James 5:13; and the encouragement to it is,
I will deliver thee: that is, out of trouble: as he is able, so faithful is he that hath promised, and will do it. The obligation follows,
and thou shall glorify me; by offering praise, Psalm 50:23; ascribing the glory of the deliverance to God, and serving him in righteousness and true holiness continually.

Call - And make conscience of that great duty of fervent prayer, which is an acknowledgment of thy subjection to me, and of thy trust and dependance upon me. Glorify - Thou shalt have occasion to glorify me for thy deliverance.