The answer
When the congregations were significantly less in number, the priest would bless each person by touching his/her head during the final benediction at the end of the Divine Liturgy. As the congregations grew, this tradition became too overwhelming and time-consuming for the limited priests to bestow these blessings individually. Thus, the priest pours a small amount of water in his hands and blesses a large amount of people at one time while praying the final benediction as he walks up and down the aisle of the church.Answered by His Eminence Metropolitan Youssef (opens in a new tab)