John Gill Commentary Psalms 105:3

"Glory ye in his holy name: Let the heart of them rejoice that seek Jehovah." — Psalms 105:3 (ASV)

Glory you in his holy name
In the knowledge of it, as proclaimed in Christ; in being called by his name, and in having the honour to call upon his name; in the holiness of it; and in Christ being made sanctification as well as righteousness, in whom all the seed of Israel are justified and glory; as they may also of interest in him, and communion with him.

Let the heart of them rejoice that seek the Lord ;
while he may be found, and where he may be found; who seek him in Christ, and under the guidance and direction of his Spirit; who seek him with their whole hearts, diligently and constantly. The Targum is, "who seek doctrine from the Lord." Such may and should rejoice in him, and in him only; and that always, as they have reason to do, even in their hearts, since they that seek him find him; and whether it be at first conversion, or afterwards, or when he has for a time hid his face; it must be matter of joy to them, even to their very hearts, to find him whom they seek.