_2dly_, It ought to be done frequently; not like those things which are to be performed but once in our lives, or only upon some extraordinary occasions, but often, at least, so often, that no presumptuous sin may be committed, nor any extraordinary judgment inflicted on us, or mercy vouchsafed to us, without a due observation thereof, in order to our improving them aright to the glory of God, and our own edification: Nevertheless, we cannot exactly determine what relates to the frequency of this duty, any more than we can prescribe to those who are in a way of trade and business in the world, how often they are to cast up their accounts, and set their books in order, that they may judge whether they go forward or backward in the world: Notwithstanding, as the neglect hereof has been detrimental to many, as to their worldly affairs; so the neglect of self-examination has been often found an hindrance to our comfortable procedure in our christian course: However, so far as we may advise concerning the frequency of this duty, it would redound much to the glory of God and our own advantage, if, at the close of every day, we would call to mind the experiences we have had, and observe the frame of spirit with which we have engaged in all the business thereof. This the Psalmist advises when he says, _Commune with your own heart upon your bed, and be still_, Psal. iv. 4. Moreover, it is adviseable for us to perform this duty whenever we engage in other solemn stated religious duties, whether public or private, that we may know what matter we have for prayer, or praise, what help we want from God, against the prevalency of corruption or temptation, or what answers of prayer we have received from him, or what success we have had under any ordinance, in which we have engaged, as well as what the present frame of our spirit is, when drawing nigh to God in any holy duty.