Psalms 73:27

27.For, lo! they who depart from thee shall perish. Here he proves, by an argument taken from things contrary, that nothing was better for him than simply to repose himself upon God alone; for no sooner does any one depart from God than he inevitably falls into the most dreadful destruction. All depart from him who divide and scatter their hope among a variety of objects. The phrase to go a whoring (210) is of similar import; for it is the worst kind of adultery to divide our heart that it may not continue fixed exclusively upon God. This will be more easily understood by defining the spiritual chastity of our minds, which consists in faith, in calling upon God, in integrity of heart, and in obedience to the Word. Whoever then submits not himself to the Word of God, that feeling him to be the sole author of all good things, he may depend upon him, surrender himself to be governed by him, betake himself to him at all times, and devote to him all his affections, such a person is like an adulterous woman who leaves her own husband, and prostitutes herself to strangers. David’s language then is equivalent to his pronouncing all apostates who revolt from God to be adulterers.