By terrible things in righteousness wilt thou answer us - That is, By things suited to inspire us and all people with awe, or with a deep sense of thy majesty, thy power, and thy glory. The answer to their prayers would be in such a manner as deeply to impress their minds and hearts. God’s judgments on his foes, and the manner of his manifesting his favor to his people, would be such as to impress the mind with a deep sense of his own greatness. Yet all this would be in righteousness; in the infliction of a just sentence on the wicked; in direct interposition in favor of the righteous. The judgments of God on guilty people have been always such as to keep the world in awe; such as were adapted deeply to impress mankind with a sense of his own majesty and glory.
O God of our salvation - The God on whom our salvation, or our safety depends.
Who art the confidence of all the ends of the earth - Of all parts of the earth, the word “ends” being used on the supposition that the earth is a plain having appropriate limits. This allusion is often found in the Scriptures, the sacred writers speaking, as all men do, as things appear to be. Thus all philosophers, as well as other people, speak of the sun as rising and setting, which is, in itself, no more strictly accurate than it is to speak of the earth as if it had limits or boundaries. The word confidence as used here means that God is the source of trust, or, that all proper reliance, by all people, in all parts of the earth and on the sea, must be in him; that is, that there is no other on whom people can properly rely. It does not mean that all people actually repose such confidence in him, which would not be true - but that he is the only true source of confidence.
And of them that are afar off upon the sea - That is, of all men on sea and land. The seaman has no other source of security amidst the dangers of the deep than God. Compare Psalms 107:23-30. The language does not mean that all mariners actually do put their trust in God, but that they cannot confide in the winds and the waves - in the strength of their vessel - or their own power or skill in managing it - but that the true and only ground of trust is God.