1 Corinthians iii. 15: "If any man's work burn, he shall suffer loss; but he himself shall be saved, yet so as by fire." - a little bit vague but has the sense of a man needing to be purified by fire (like precious metals) before entering heaven ("[being] saved").
St Matthew v. 20: "For I tell you, that unless your justice abound more than that of the scribes and Pharisees, you shall not enter into the kingdom of heaven."
2 Corinthians xi. 2: "For I am jealous of you with the jealousy of God. For I have espoused you to one husband that I may present you as a chaste virgin to Christ."
Hebrews xii. 14: "Follow peace with all men, and holiness: without which no man shall see God."