To be with God is life; to be far from Him is death. The psalmist’s realization of this fact solved the problem of God’s dealings with men (see vs. 3-12).
Go a whoring.
God’s relation to His people is frequently compared to that of marriage (see Ps. 45; Jer. 3:8, 9, 14; 5:7; 13:27; 2 Cor. 11:2; Eph. 5:25; James 4:4). When God’s children are estranged from Him, they are unfaithful to their marriage vows. The phrase “a whoring” consists of the preposition “a” and the verbal noun “whoring.”