William Gouge, The Saints' Sacrifice, or a Commentary on Psalm CXVI, p. 34 (re Ps. 116.5):
Sec. 30. Of God's greatness and goodness agreeing in one.
IV. The great Lord is a good God. He that is Jehovah, the Eternal, that hath his being of himself, and is all-sufficient in himself, even he is gracious and righteous and merciful. His greatness is no way any hindrance to his goodness, but rather a help thereto. Where this incomprehensible name of his is, for emphasis' sake, twice together proclaimed, and another word added thereto that sheweth him to be a mighty God, there the titles of his mercy, grace, patience, and goodness are also proclaimed; thus, 'The Lord, the Lord, the strong God, merciful and gracious,' &c. Exod. xxxiv. 6, [Heb.] again, where Moses thus setteth out God's excellency, 'The Lord your God is God of gods and Lord of lords, a great God, mighty and terrible, which regardeth not persons, nor taketh reward,' he addeth in demonstration of his goodness, 'He doth execute the judgment of the fatherless and widow, and loveth the stranger in giving him food and raiment,' Deut. x. 17, 18; and in that perfect pattern of prayer where the Lord is set out in his high and glorious palace in heaven, there is he styled 'our Father,' Mat. vi. 9; and in most of the solemn prayers of the saints recorded in Scripture, there are express titles of both these divine properties, God's greatness and goodness, whereby they shewed that, notwithstanding that knowledge which they had of God's excellent majesty, they believed him to be a gracious and merciful Father, tendering them as impotent succourless babes, and thereupon, though in regard of that throne of glory whereon he sitteth, they are affrighted, as Isaiah was, Isa. vi. 5; yet knowing that throne of glory to be also a throne of grace, a mercy-seat, they are emboldened to approach thereunto that they may 'obtain mercy, and find grace to help in time of need,' Heb. iv. 16.
Both these are revealed to be in God, to manifest the absolute perfection of his excellency; for, there is an excellency in both, and by the concurrence of both is excellency perfected. Greatness without goodness might give suspicion of tyranny. Goodness without greatness might import impotency. But a mixture of goodness with greatness demonstrates a willing ability, and an able willingness; from whence what may not be hoped for and expected?