Albert Barnes Commentary Psalms 5:11

"But let all those that take refuge in thee rejoice, Let them ever shout for joy, because thou defendest them: Let them also that love thy name be joyful in thee." — Psalms 5:11 (ASV)

But let all those that put their trust in thee rejoice - (Compare the notes at Psalms 2:12). That is, they have occasion to rejoice in you and in your protection. The wicked have everything to dread, for they must be cut off; but the righteous have every reason to be happy, for they shall partake of the favor of God. This is, at the same time, the earnest expression of a desire that they might rejoice, and that God's dealings with them might be such that they would ever "have occasion" for joy.

Let them even shout for joy - Internal joy or happiness is often expressed by shouting, or singing, as the word used here frequently signifies. The meaning is, that they should give every proper expression to their feeling of joy. This may be done by singing, or by grateful ascriptions of praise and gratitude.

Because thou defendest them - While the wicked are cut off (Psalms 5:10). The psalmist, in this expression, doubtless had a primary reference to himself and to those who adhered to him in his righteous cause; but, as is common in the Psalms, he gives to the sentiment a general form, that it might be useful to all who fear and love God.

Let them also that love thy name - That love you - the name often stands for the person. This is just another way of designating the righteous, for it is one of their characteristics that they love the name of God.

Be joyful in thee - Rejoice in you - in your existence, your perfections, your government, your law, your dealings, your service; in all that you have revealed of yourself, and in all that you do. (Compare Philippians 3:1, note; Philippians 4:4, note). It is one of the characteristics of the truly pious that they do find their happiness in God. They rejoice that there is a God, and that he is just such a being as he is; and they take delight in contemplating his perfections, in the evidences of his favor and friendship, in communion with him, in doing his will.