Matthew Henry on Psalms 138:6-8

Though the Lord is high, yet he has respect to every lowly, humbled sinner; but the proud and unbelieving will be banished far from his blissful presence. Divine consolations have enough in them to revive us, even when we walk in the midst of troubles. And God will save his own people that they may be revived by the Holy Spirit, the Giver of life and holiness. If we give to God the glory of his mercy, we may take to ourselves the comfort. This confidence will not do away, but quicken prayer. Whatever good there is in us, it is God works in us both to will and to do. The Lord will perfect the salvation of every true believer, and he will never forsake those whom he has created anew in Christ Jesus unto good works.