“In vain do they worship me, teaching as doctrine the commands of men” (Mark 7:7).
There are churches that teach the eating of certain meals for so-called Holy days, holidays, or other days of the week. In the Old Testament the people were commanded to eat certain foods (Leviticus 11). But we are not under the Old Testament any more. We are under the New Testament (Hebrews 8:6-13; 2 Corinthians 3:6). Under the New Testament, any kind of food is good and can be eaten, providing we give thanks (1 Timothy 4:1-5).
Another law made by men is “denying marriage to priests.” In the New Testament all Christians are priests with Jesus being the High Priest (1 Peter 2:5,11; Hebrews 4:14-15).
Since God did not authorize the office of priests as some teach, the ‘no marriage’ rule goes out the window. However, notice who can marry according to the Bible: