Abraham offered sacrifices to God and called on the name of the Lord. (Gen. 12:8, Gen. 13:4, Gen. 21:33)
Gen. 12:8 And he removed from thence unto a mountain on the east of Bethel, and pitched his tent, having Bethel on the west, and Hai on the east: and there he builded an altar unto the Lord, and called upon the name of the Lord.
Gen. 13:4 Unto the place of the altar, which he had make there at the first: and there Abram called on the name of the Lord.
Gen. 21:33 And Abraham planted a grove in Beersheba, and called there on the name of the Lord, the everlasting God.
Seth gave birth to a son, and at that time people called on the name of the LORD. (Genesis 4:26)
Genesis 4:26 And to Seth, to him also there was born a son; and he called his name Enos: then began men to call upon the name of the Lord.
The Old Testament prophesies that those who call on the name of the Lord will be saved. (Joel 2:32)
Joel 2:32 And it shall come to pass, that whosoever shall call on the name of the Lord shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the Lord hath said, and in the remnant whom the Lord shall call.
Those who believe that Jesus is the Christ and call on the name of Jesus will be saved. (Acts 2:21, Romans 10:13)
Acts 2:21 And it shall come to pass, that whosoever shall call on the name of the Lord shall be saved.
Romans 10:13 For whosoever shall call upon the name of the Lord shall be saved.