"The Truth," a religion
Many Christians believe that the Bible is the Word of God and entirely true. In this view, it is the holy guide and one must adhere to it entirely or ask forgiveness.
American protestants call selective belief "picking and choosing," dismissive of any attempt at discernment.
But many of the prescriptions in the Bible are unsuitable outside of a specific culture. In these cases, it is acceptable to think of these requirements as inapplicable. Believers do not seem to consider this a contradiction.
Also, Christians believe that Jesus' love supercedes the Old Testament laws of specific instruction. But there is no concensus about which parts of the Old Testament are no longer applicable.
So in practice, a believer must discern.
In other words, one must "pick and choose." This is acceptable if a group does it but it's not to be done by individual discretion. At least that's the convention.