Albert Barnes Commentary Psalms 63:3

"Because thy lovingkindness is better than life, My lips shall praise thee." — Psalms 63:3 (ASV)

Because thy loving-kindness is better than life - Your favor; your mercy. This is of more value than life; more to be desired than life.

Life is the most valued and valuable thing pertaining to this world which we can possess (see the notes at Job 2:4).

But, above this, David valued the favor and friendship of God. If one or the other was to be sacrificed, he preferred that it should be his life; he would be willing to exchange that for the favor of God.

Life was not desirable; life furnished no comforts—no joys—without the divine favor.

“My life itself, without Your love,
No taste of pleasure could afford;
It would but a tiresome burden prove,
If I were banished from the Lord.”

My lips shall praise thee - That is either:

1. Because of this loving-kindness; because I have this trust in your character; or
2. Because you will restore me to the place of public worship, and I shall be permitted again to praise you.

Probably the latter is the true idea.