Sometimes I sing only within my heart to Jesus which constitutes praying to Him.
Ephesians 5:19
Speaking to one another in psalms and hymns and spiritual songs, singing and making melody with your heart to the Lord.
Just in case there is any confusion, "the Lord" refers to Jesus.
τῷ κυρίῳ in 5:19 with τῷ κυρίῳ in 5:22
Ephesians 5:19-24
(19) speaking to one another in psalms and hymns and spiritual songs, singing and making melody with your heart to the Lord;
(20) always giving thanks for all things in the name of our Lord Jesus Christ to God, even the Father;
(21) and be subject to one another in the fear of Christ.
(22) Wives, be subject to your own husbands, as to the Lord.
(23) For the husband is the head of the wife, as Christ also is the head of the church, He Himself being the Savior of the body.
(24) But as the church is subject to Christ, so also the wives ought to be to their husbands in everything.