My soul shall make her boast in the Lord - I myself will rejoice and exult in him. The word “boast” here refers to that on which a man would value himself; that which would be most prominent in his mind when he endeavored to call to remembrance what he could reflect on with most pleasure. The psalmist here says that when He did this, it would not be wealth or strength to which he would refer; it would not be his rank or position in society; it would not be what he had done, nor what he had gained, as pertaining to this life. His joy would spring from the fact that there was a God; that he was such a God, and that he could regard him as His God. This would be his chief distinction - that on which he would value himself most. Of all the things that we can possess in this world, the crowning distinction is, that we have a God, and that he is such a being as he is.
The humble shall hear thereof - The poor; the afflicted; those who are in the lower walks of life. They should hear that he put his trust in God, and they should find joy in being thus directed to God as their portion and their hope. The psalmist seems to have referred here to that class particularly, because:
(a) they would be more likely to appreciate this than those of more elevated rank, or than those who had never known affliction; and
(b) because this would be specially fitted to impart to them support and consolation, as derived from his own experience.
He had been in trouble. He had been encompassed with dangers. He had been mercifully protected and delivered. He was about to state how it had been done. He was sure that they who were in the circumstances in which he had been would welcome the truths which he was about to state, and would rejoice that there might be deliverance for them also, and that they too might find God a protector and a friend. Calamity, danger, poverty, trial, are often of eminent advantage in preparing the mind to appreciate the nature, and to prize the lessons of religion.
And be glad - Rejoice in the story of my deliverance, since it will lead them to see that they also may find deliverance in the day of trial.