They made some excuse that the limited number of regenerations was something imposed by the Time Lords, and now that The Doctor is the only Time Lord left there is no one to enforce that rule on him.
Romans 8:31 What, then, shall we say in response to this? If God is for us, who can be against us?
1 Corinthians 13:1-3 If I speak in the tongues of men or of angels, but do not have love, I am only a resounding gong or a clanging cymbal. If I have the gift of prophecy and can fathom all mysteries and all knowledge, and if I have a faith that can move mountains, but do not have love, I am nothing. If I give all I possess to the poor and give over my body to hardship that I may boast, but do not have love, I gain nothing.