Now unto him that is able to keep you from falling, and to present you faultless before the presence of his glory with exceeding joy, Now unto him that is able to keep you from falling - Who alone can preserve you from the contagion of sin, and preserve you from falling into any kind of error that might be prejudicial to the interests of your souls; and thus to present you faultless, or, as many others read, ασπιλους, without spot, alluding to the spotted garment mentioned above.
Before the presence of his glory - Where nothing can stand that does not resemble himself, with exceeding great joy, in finding yourselves eternally out of the reach of the possibility of falling, and for having now arrived at an eternity of happiness.