Once have been baptized we can continue to commit sins. Once committed a sin how we can be sure in our salvation?
The Bible is against the idea of OSAS.
1 Corinthians 6,9: Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind
Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.
Are those words about non-believers only or about those who have been baptized as well?
Paul wrote his epistle to the church of Corinth. So he wrote to the church people.
Nevertheless in the same epistle we can find the confirmation that even brothers can commit such sins as written in previous quote.
1 Corinthians 5,9: I wrote unto you in an epistle not to company with fornicators: Yet not altogether with the fornicators of this world, or with the covetous, or extortioners, or with idolaters; for then must ye needs go out of the world But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolater, or a railer, or a drunkard, or an extortioner; with such an one no not to eat. For what have I to do to judge them also that are without? Do not ye judge them that are within? But them that are without God judgeth. Therefore put away from among yourselves that wicked person