The doubts of this verse concern a multitude of realities as offered by John Gill. There are thoughts of the majesty of God and how we relate to him. It is offered that we sense security yet an uncertainty at the same time. We believe we have hope but are consumed with hopelessness; saved but lost; sure but doubtful at the same time. It is a struggling desire to be all God created us to be, realising we can never attain to that image; waiting for heaven but never sure it will come.