Anointing oil was used to be a blessing to someone chosen by God, especially for a special task. David was anointed king. Aaron was anointed to be the leader of the priesthood. Many were anointed to the service of God.
The oil of gladness is poured out on those who have mourned and now are receiving the love and comfort from the Lord. We mourn our past sins and the Lord honors our choice to move them to the past. He wants us to learn from them, not repeat them, and to help others learn from our mistakes as well.
He pours on us the oil of gladness. He asks us to come into His presence with singing and rejoicing in His forgiveness. He rejoices over us with singing. The angels rejoice over a repentant sinner. He gives a sweet fragrance of love to all who call on His Name.
Father, how we love and adore You. We come into Your presence, knowing we will be received with joy. We have been washed in the blood of the Lamb and anointed with the oil of gladness.