Why did many Protestant Reformers recognize only baptism and the Eucharist as sacraments?

Protestant Reformers in the 16th century limited the number of sacraments to baptism and the Eucharist because they redefined a sacrament as a rite explicitly commanded by Christ in the Scriptures.12

While the Roman Catholic Church had established seven sacraments—baptism, confirmation, the Eucharist, penance, holy orders, matrimony, and anointing of the sick—Reformers argued that the five additional rites did not meet the criteria of being instituted by Christ to impart grace.132

For example, Martin Luther rejected marriage as a sacrament because he believed it was instituted by God in the Garden of Eden rather than by Christ, and it was not exclusive to Christians. Although many Protestant churches continued to practice these rites, they were no longer classified as sacraments, as they were viewed either as civil acts or as lacking the specific divine institution required to convey grace.21