'Lawful' in the Bible

And Philip said, 'If thou dost believe out of all the heart, it is lawful;' and he answering said, 'I believe Jesus Christ to be the Son of God;'

He said to them, “You know that it is unlawful for a Jewish man to associate with or befriend a Gentile, or to visit him; and yet God has shown me that I am not to call anyone common or [ceremonially] unclean.

And teach customs, which are not lawful for us to receive, neither to observe, being Romans.

But if ye inquire any thing concerning other matters, it shall be determined in a lawful assembly.

And as they bound him with thongs, Paul said unto the centurion that stood by, Is it lawful for you to scourge a man that is a Roman, and uncondemned?