Create in me a clean heart,O God; and renew a right spirit within me.Cast me not away from thy presence; and take not thy holy spirit from me.Restore unto methe joy of thy salvation; and uphold me with thy free spirit. Thenwill Iteachtransgressorsthy ways; and sinnersshall be converted unto thee.

-Bible (Old Testament)
Psalms 51:10^13.

And said,Verily I say unto you, Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven.

-Bible (NewTestament)
St Matthew18:3