Soprano Kiri Te Kanawa personified the noblesse of a singer’s maturity as she performed Saturday night as part of the Israel Festival. The sheer beauty of her voice was enhanced by her radiating an increased dimension of delicacy, and the consummate artistry of shaping a musical phrase. Her way of reaching the highest notes with effortless ease and caressing softness, and then letting it swell to persuasive force represents an achievement of fabulous voice culture. Whether low or high, her tones are always absolutely pure, and her expression is intense without ever becoming assertive.Her profound identification with Richard Strauss’ refined optimism in Tomorrow was one of the recital’s highlights. In the Argentinian songs by Guastavino and Ginastera she displayed a captivating discreet charm. Her generosity of spirit was evident by her presenting one of her young protegees, Phillip Rhodes, in the course of her recital. His appealing baritone and extraordinary expressive talent were such as to excite the audience and to justify her confidence in his artistic potential.Michael Pollock collaborated most attentively at the piano, sensitively adjusting his playing’s volume to the singer’s subtlest nuances.