Why is the prayer of the upright his delight? Because the joy that our Father gives is lasting and remains forever, because when He arrives, our sadness changes to eternal joy.
When we pray to our Lord we do it with love, also when we have some kind of problem, we go before God and ask for everything to be resolved in peace.
Even when we are in good times, we feel joyful and glorify God for that, because when certain proof come, if we are not within that joy and that peace of God, faith can fail as we would not endure.
The sacrifice of the wicked is an abomination to the Lord: but the prayer of the upright is his delight.