John Calvin Commentary Psalms 84:5

"Blessed is the man whose strength is in thee; In whose heart are the highways [to Zion]." — Psalms 84:5 (ASV)

Blessed is the man whose strength is in you. David again informs us that the purpose for which he desired freedom of access to the sanctuary was not merely to gratify his eyes with what was to be seen there, but to make progress in faith. To lean with the whole heart on God is to attain a high degree of spiritual advancement; and this cannot be attained by anyone unless all their pride is laid prostrate in the dust and their heart truly humbled.

In choosing this way of seeking God for himself, David’s object is to borrow from Him by prayer the strength of which he feels himself to be destitute. The concluding clause of the verse, the ways are in their hearts, is interpreted by some as meaning, That those are happy who walk in the way God has appointed; for nothing is more harmful to a person than to trust in their own understanding.

It is rightly said of the law, This is the way, walk you in it (Isaiah 30:21). Whenever, then, people turn aside, however slightly, from the divine law, they go astray and become entangled in perverse errors. But it is more appropriate to limit this clause to the context of the passage and to understand it as implying that those are happy whose highest ambition is to have God as the guide of their life, and who therefore desire to draw near to Him.

God, as we have previously observed, is not satisfied with mere outward ceremonies. What He desires is to rule and keep in subjection to Himself all whom He invites to His tabernacle. Whoever, then, has learned how great a blessing it is to rely on God, will direct all the desires and faculties of their mind, so that with all speed they may hasten to Him.